A Very Rough Guide to How I Personally Define Different Genres and Subgenres

Sorting books by genre can be notoriously tricky. A lot of people think of genre is as nothing more than a marketing tool, and sometimes, it is. If a book is on the fantasy shelf at the bookstore, it means it's being marketed to fans of other popular fantasy books. At the same time, the concept of genre predates modern booksellers by millennia. When Ancient Greek poetry was sorted into lyric and epic forms, the distinction had very little to do with sales.

The truth is that there are descriptive definitions of genres, and there are commercial definitions. Both are always changing and interacting. The descriptive definition of fantasy is usually something along the lines of: any story that explores impossible, magical, and unreal worlds or situations. The commercial definition means that magical realism ends up on the literary fiction shelf more often than not, while a lot of haunted-house stories can be found in the horror section, and ancient epics about gods fighting each other is usually considered a work of classical mythology or something like that. Fantasy ends up being more narrowly about what fans of J.R.R. Tolkien and George R.R. Martin would enjoy.

In short, every genre has a lot of different definitions. Thankfully, in a digital space like this one, I can easily put the same book on multiple shelves. No need to decide if Emily Wilde's Encyclopaedia of Faeries is fantasy, romantasy, or hitorical fiction. It can be all of the above and more. That doesn't mean sorting books in this way is always easy. Some books are borderline. Only one or two of the Emily Wilde books adhere to the somewhat strict conventions of the romance genre, while the rest may count as a love story without really being a romance. In the end, I did shelve Emily Wilde's Encyclopaedia of Faeries as romance, and if that judgment call confuses you, totally fair. Below I've put together a rough explanatory guide for people curious about how I've decided to define different genres and subgenres:

Absurdism: Absurdist fiction explores stories that feature a lot of seemingly purposeless human behavior. This does not mean the behavior is always illogical. It just means that society has provided characters with motivations and goals that can't be reached or that don't seem to matter at all. I will generally stick a book on the absurdism shelf if the story feels like it obeys the logic of a frustration dream.
Afrofuturism: These are futuristic books that deal with characters who are from Africa or the African diaspora, while the themes tend to speak to the concerns of people who are from modern-day Africa or the modern-day African diaspora. Since modern-day Africa and the modern-day African diaspora together include a whole lot of people who have a whole lot of diverse concerns, it's very easy for a book to end up on my Afrofuturism shelf.
Alternate history: Technically all fiction that takes place in Earth's past is alternate history. Otherwise the book would be nonfiction rather than fiction. But alternate history as a literary genre focuses specifically on the question of what would happen if the outcomes of major historical events turned out differently: What if Germany won the First World War? What if Emperor Qin Shi Huang actually managed to drink the elixir of life? That sort of thing. There is room to debate what counts as a major historical event. I generally stick a book on this shelf if I personally can name the major historical event, movement, or era upon which the book turns. The book does not have to be set in the past. It can be set in an alternate present or future that is shaped by an alternate past.
Bildungsroman: This is your classic coming-of-age story. On a technical level, coming-of-age is a broader term than bildungsroman. Bildungsromans have formal, topical, and thematic constraints, whereas a coming-of-age novel just means a protagonist is a certain age. However, the constraints of the bildungsroman have been deliberately subverted in so many major instances at this point, so I use bildungsroman and coming-of-age more or less interchangeably. Basically, if the novel isn't already YA but does feature younger characters growing up (not as part of the backstory, but as part of the actual narrative), then the novel is going to be shelved as bildungsroman. It's basically my way of saying a book isn't YA, but it does feature young adults. Some YA books may also be shelved as bildungsroman if they adhere strictly the technical constraints of the bildungsroman genre -- that is, they're about moral growth and finding a place in society, usually structured around three acts.
Biopunk: The term biopunk used to refer to books about genetic manipulation. I use the term more broadly than that. Basically if biotech is a major part of the plot or worldbuilding, then there's a good chance it's biopunk. I also do expect the book to fit with the anti-authoritarian punk aesthetic, but I tend to generous about whether a book can be considered anti-authoritarian. If there is any critique whatsoever in there against tyranny or oppression, then I count it as punk.
Choose your own adventure: aka pick-a-path aka CYOA. This is where the reader acts as the protagonist and makes choices that determine how the plot plays out. There are usually multiple iterations of the story, and it's up to the reader to decide which path to take.
Climate Fiction: aka clifi. This genre frequently imagines potential futures for humanity, portraying the ways we might respond to climate change. A book about the next Ice Age can also count as climate fiction; it doesn't have to feature the same version of climate change that we're all familiar with. The book doesn't even have to be set on Earth. As long as the climate is changing, it's clifi.
Comedy: If humor is a major part of the appeal, then I shelve it as comedy.
Contemporary: If at least part of the book takes place in the modern day with characters dealing with modern-day concerns, then I shelve it as contemporary.
Cozy: If the stakes aren't world-ending, and the characters are wholesome, then it's cozy. Sometimes the stakes can still actually be world-ending, as long as you kind of know not to take those stakes too seriously. These books tend to be very gentle, quirky, affirming, comforting, and even healing.
Crime: Any novel that centers arounda crime. It tends to be an umbrella term for a lot of genres. The main character might be investigating the crime, in which case you'll have a crime mystery novel. The main character might be doing and trying to get away with a crime, in which case you might have something like a thriller or a heist or both. You may also have a book about surviving an environment with a lot of violent crime, which might look more like an urban fiction book.
Cyberpunk: A subgenre of science fiction, cyberpunk is often described as "low life but high tech." Society is dystopian. Wealth disaprities are heightened. Megacorporations are running everything. The technologies themselves usually revolve around AI, surveillance, information, virtual reality, and software that interfaces with the human brain or body.
Dark academia: The dark academia literary tradition involves portraying the dark side of academic settings, often telling stories about classicism, burnout, and the academy's dark history with things like slavery and eugenics. It's not anti-intellectual, but it is a critique of academia. At the same time, dark academia is also an aesthetic that was inspired by a grown-up reinterpretation of the vibes at Hogwarts. A book can, technically, fit that aesthetic without including any content about the dark side of academia. And in fact, the aesthetic tends to romanticize rather than criticize academia. Somehow these two seemingly antithetical strands have collided to create a genre that is very loosely defined. When I read dark academia, I do expect some sort of critique of the academy, but I also recognize that a lot of readers simply expect a book that features a school, while others just want a book that would make a good accessory for the dark academia aesthetic (usually a moody Victorian gothic horror novel that is often assigned as mandatory reading in high school). So I'm generous. If scholars, students, or academics play a major role in the story, and if that story isn't purely lighthearted, then I'll shelve it as dark academia.
Decadent: Decadent literature features stories about the celebration of hedonism over traditional morality.
Domestic: Domestic fiction books focus on home and family life. They are very intimate. They tend to veer more towards realism than the fantastical, but that's not a hard and fast rule. As long as the domestic scenes themselves have some measure of realism, then I'll count it as domestic.
Dystopia: Characters navigate a society where the the state is an antagonistic force, or at least incapable of doing anything about other antagonistic instituions (like evil corporations).
Environmental horror: aka eco horror. Horror books where nature itself is hostile. Natural forces often serve as the primary antagonist.
Epic fantasy: A subgenre of fantasy. The stakes are high. The scope is wide. There's usually a lot of perspective characters, though not always.
Epistolary: All (or a significant portion) of the narrative is told through documents: letters, emails, newspaper clippings, scholarly articles, diary entries, etc.
Fairy tale: There's a lot of debate about this one, so I go by vibes. If there are fairies, I'm shelving it as fairy tale. If it's a retelling of something lie Snow White, then I'm shelving it as fairy tale. If it's explicitly concerned with folklore, then I'm shelving it as fairy tale. And, of course, if it is a traditional fairy tale about princesses and talking animals, then I'm shelving it as fairy tale.
Family saga: Traces the lives of multiple generations in the same family, covering a large time frame.
Fantasy: Explores impossible, magical, and unreal worlds or situations.
Feminist: Deals with feminist critiques of patriarchy, usually featuring female protagonists who subvert various societal expectations.

Gaslamp: Subgenre of fantasy. Usually has a Regency, Victorian, or Edwardian Era aesthetic. Although the Industrial Revolution might be happening in the backdrop, the main focus of the story is on magic, intrigue, and interpersonal relationships.

Ghost story: If there's a ghost, it's a ghost story.
Gothic: Gothic books deal with the past haunting the present. Usually a subgenre of horror. Expect from these books nonlinear storytelling, old manuscripts, a lot of scenes featuring physical of rot and decay, examples of moral rot and decay as well, some immortal or undead creature or ghost, dark secrets from the past that don't like to stay buried, and social commentary about how we probably shouldn't romantacize the past. Not all of those tropes feature, but those are common tropes, all used in service to portraying an atmosphere of haunting.
Grimdark: Subgenre of fanatasy. Features amoral protagonists navigating amoral worlds.
Heist: aka caper. A memorable ensemble of people (usually criminals) get together to pull off some sort of seemingly impossible job.
High fantasy: Fantasy not set on Earth. (In some cases, it can be set on Earth, but on a version of it that is so unrecognizable at every level that you could stick the entire plot on a different planet and nothing would fundamentally change. These books tend to feature a lot of magical abilities, magical creatures, and magical races.)
Historical: Stories that take place in the past. These books are set during a historical time period that predates when the book was published.
Hopepunk: Subgenre of speculative fiction. The opposite of grimdark. These books are about fundamentally good people just doing their best to solve problems, usually systemic problems. If a speculative fiction book feels cozy but the stakes are too high or the content is too dark for me to shelve it there, then I usually shelve it as hopepunk.
Horror: Books that explore our biggest fears. Often designed to frighten, unsettle, or shock.
Literary: aka litfic. Another highly controversial genre. People claim that literary fiction is a book that meditates on the human condition, focusing on prose and characters more than on plot. That, in my opinion, is a terrible definition. Quite simply, literary fiction is just the opposite of genre fiction. Nothing more. Nothing less. If a book doesn't really have a good genre label, then it's literary fiction. Sometimes, even if a book does have a good genre label but it probably can't be easily marketed to fans of that genre, then it'll instead be marketed as literary fiction. And yes, litfic often does meditate on the human condition, focusing on prose and character more than on plot. The same is true of a lot of genre fiction, but it's more of a guarantee when it comes to literary fiction. I also shelve books at litfic if they've entered the Literature Canon, by which I mean, if you're likely to study it in high school or college, then I'm counting it as litfic.
LitRPG: Literature plus role-playing games. The world that the characters navigate has gamified elements: things like damage and experience can be quantified, and there's often a quest or goal at the center of the narrative.
Lovecraftian: aka cosmic horror aka weird fiction aka new weird aka eldritch horror. Technically all these terms refer to slightly different things, but I'm using Lovecraftian as a blanket term for books that focus on the horror of fathoming the unfathomable. The monsters are too big to comprehend. You go mad when you look at them directly. They treat humans like ants. Sometimes the monsters are aliens from alternate dimensions. Sometimes they're even weirder than that -- houses that don't obey the rules of physics or geometry, or entire forests that have might have gained sentience, or strange anomalies in time and space.
Magical realism: Originating in Latin America in response to specific historical contexts, magical realism has since ballooned into a genre that merges the magical with the mundane. To fantasy fans, that might sound like a lot of urban fantasy, but there are differences. The magical in magical realism is never really part of anything resembling worldbuilding. It's often utilized to evoke certain emotions or touch on certain themes. The same is true, however, of plenty of genre fantasy books, so maybe magical realism can be subsumed by fantasy (specifically urban fantasy) if you squint. If it is, it's definitely more on the literary side of things, at least nowadays. I'd also add that sometimes you can't even tell if the magic in these books is superstition, actual magic, or all in someone's head. It's wide open to interpretation whether the story is fantastical at all. Other times it's not open to interpretation in the same way, and you know that magic is real, but there's still usually something very metaphorical about it.
Mosaic novel: Individual chapters often read as short stories, but each story shares a collection of characters or settings.
Mystery: Focuses on solving a puzzling event, often a crime.
Mythology: If a book belongs to a culture's mythological tradition, I shelve it as mythology. If a book features characters or creatures that are very specific to a mythological tradition, I may also shelve it as mythology. If a book is a mythological retelling, I shelve it as mythology.
Noir: A grittier and more cynical version of the traditional detective story. There's corruption, anti-heroic tendencies from the protagonists, no pure villains, and bleaker endings.
Novella: A novel that is usually around one hundred pages.
Occult: Subgenre of horror and fantasy dealing with discovering dangerous hidden knowledge and performing dangerous secret rituals.
Paranormal: Books where humans live alongside other intelligent races like werewolves and vampires.
Philosophy: Books that explicitly engage in and make philosophical arguments.
Picaresque: Books whose structures involve episodic adventures.
Poetry: There isn't really a good definition of poetry. If a book explicitly claims to be poetry, then I shelve it as such.
Political intrigue: Books where characters must navigate the game of politics. There's strategizing, manipulation, and spying. Alliances form and disolve. It's not always high-octane, but there usually are high stakes.
Politics: Books that explicitly engage in and make political arguments.
Portal fantasy: Books that start in one place (usually the mundane world), but characters end up whisked away elsewhere.
Progression fantasy: Features characters gaining skill, powers, and abilities. These gains can be quantified.
Psychological thriller: Thrillers that don't always feature clear external antagonists. The internal threats are where the tension often comes from. Pacing is much slower than in a traditional thriller, but the suspense and danger is still there.
Queer: If the main character is queer, then I'm shelving it as queer. If the book deals explicitly with queer themes, then I'm shelving it as queer.
Quest: Often a subgenre of fantasy, but not always. The narrative focuses on characters going on an adventure or journey of some sort with a specific goal or destination in mind.
Retellings: The novel retells or reinterprets an older story.
Romance: There is technically a strict definition of a romance book. It needs to have a third-act breakup and a happily-ever-after and a bunch of other things. I'm sorry to say that I'm ignoring that definition. Some people just want to know if a book features a romantic subplot. They don't actually care if it rigidly adheres to genre conventions. So any book that prominently features a love story gets shelved as romance by me. If it ends tragically, it's still a romance. If the chemistry is nonexistent, it's still a romance. If the love story is only a small subplot, it's still a romance. I know this'll make some romance readers angry. My one defense is that romance readers have it so easy compared to everyone else. More romance get published than any other genre, and there are tons of available resources out there to help you properly identify a romance book. For example, check out romance.io.
Romantasy: Fantasy that heavily focuses on romance and romantic tension.
Satire: Uses certain forms of humor, especially irony, to critique society and its institutions.
Science fantasy: A combination of scifi and fantasy. For example, maybe there are futuristic scifi technologies, but there's also magic that doesn't have any scientific basis. Or maybe there's a hard magic system that is so mechanical and scientific that it's used in a way that feels more in line with traditional scifi than fantasy.
Science fiction: aka scifi. Explores worlds and situations that aren't real in our current world but could be real based on actual or projected technology.
Short stories: A story that is roughly under ten thousand words. This shelf also incudes longer books that act as a collection of short stories.
Slice of life: Depicts everyday experiences. The plots may lack structure.
Solarpunk: It's like cyberpunk, but more hopeful. Instead of dystopias, you get something closer to utopias. Technology often functions as a force for good.
Southern gothic: Subgenre of gothic fiction. Concerned with exposing various myths related to the American South. It often features stories that deconstruct and warn against romanticizing the Antebellum.
Speculative fiction: All fiction is technically speculative. Otherwise it would be nonfiction. However, the speculative fiction genre is more of an umbrella genre that encompasses scifi, fantasy, some horror (if there are supernatural or paranormal elements), dystopia, alternate history, some magical realism, mythology, and really any story that departs markedly from the real.
Steampunk: Subgenre of fantasy and scifi set during an Industrial Revolution. Steam technology often plays a major role in the plot or worldbuilding. Clockwork technology may also be important.
Supernatural: Story where supernatural entities (like gods, demons, devils, angels, and any other being that exists above the rules of nature) exist.
Surrealism: The rules that you're familiar with go out the window. Reality is bent, disorted, inverted, and turned into something unrecognizable, yet still somehow true on an emotional level. I will generally stick a book on the surrealism shelf if the story feels like it obeys the logic of a fever dream.
Thriller: Thrillers are very plotty books focused on suspense and action.
Travel: Books that prioritize journey, exploration, and cultural immersion.
Urban fantasy: Subgenre of fantasy. These books are set in worlds (oftentimes our own) that have access to modern technology.
Urban fiction: Fiction that focuses on urban life, usually portraying the grittier side of things. These books are concerned with honest stories about harsh socioeconomic realities in cities. You tend to see a lot of crime, poverty, sex work, and systemic struggles.
War: The war story is a book about a war, usually one that really happened. These books tend not to glorify war, instead exposing the moral and psychological side of what it means to experience armed conflict, either as a civilian or a soldier.
Western: Books about life on the American frontier.
Young adult: Books that people between the ages of 12 and 18 are expected to enjoy. Contrary to popular belief, young adult is more than a mere marketing term. It might have started out that way, but there are conventions to this genre, and it is blooming into an actual literary genre with specific traditions and an actual fandom. What you can expect: the protagonist is in their teens, the content can be extremely dark but not too explicit, the storytelling is highly emotional, and the prose is pretty accessible.
Yuri: aka GL aka girl's love. Focuses on intimate relationships between women. These books are often queer.