Omegaverse Glossary: A/B/O Terms Explained

Read one A/B/O pitch and you will hit five words that mean something specific and nothing obvious: presented, unbonded, scent-blind, nesting, true mate. This omegaverse glossary defines them the way writers actually use them, not the way a summary article guesses at. Learn the vocabulary and every pitch in the room becomes readable.

One thing to hold onto before the list starts: there is no canon. Omegaverse is fanon, built collectively across a decade of fic, and every writer's version differs in the details. What follows is the common ground, with the main variations noted. When two people disagree about how knotting works, they are both right and they should sort it out before the scene, not during it.

Secondary genders

• Secondary gender. The A/B/O layer that sits alongside ordinary gender rather than replacing it. A character can be a woman and an alpha, a man and an omega, any combination. Most fanon treats it as the thing that determines social position.
• Alpha. The dominant secondary gender in most versions. Ruts, a knot, strong scent output, an instinct to protect or possess. Common failure mode in writing: playing the instinct instead of the person.
• Beta. The middle and the majority. Weak or absent cycles, muted scent, no knot. Often written as the ordinary one, which makes betas the most underrated role in the room: a beta in an alpha and omega story has to want things for reasons that are entirely their own.
• Omega. Heats, heightened scent, nesting instinct, and in most fanon the ability to carry. Frequently written as socially constrained, which is where a lot of the genre's plot comes from.
• Presenting. When a character's secondary gender emerges and becomes known. Late presentation, mispresentation and hidden presentation are all standard plots.
• Dynamic. A common synonym for secondary gender. "What's your dynamic" means alpha, beta or omega.

Biology and cycles

• Heat. The omega cycle. Recurring on a rough schedule, lasting days, intense enough to derail everything else. The single most-written scenario in the genre.
• Rut. The alpha counterpart. In most fanon it is triggered by proximity to a heat rather than arriving on its own calendar, which is why rut scenes tend to start in the middle of something.
• Knot. The anatomical feature at the base of an alpha's cock, which swells during sex.
• Knotting / the tie. The act, and the period afterwards where the two characters cannot separate. Structurally it is a gift to writers: it forces a long, immobile, intimate stretch into the middle of a scene.
• Scent. The genre's second language. Characters read mood, arousal, health, fear and bond status by smell. Scent descriptions are personal signatures: cedar, rain, bergamot, whatever your character carries.
• Scent gland. Where it comes from, conventionally at the neck and often the wrists. Also where a bond bite lands, which is why necks carry so much weight in this genre.
• Scenting. Deliberately putting your scent on someone: nuzzling the neck, wrists on skin, lending clothes. Affectionate, not necessarily sexual.
• Scent marking. The stronger version, meant to be read by others. A claim written in a language everyone in the room can smell.
• Pheromones. The catch-all mechanism behind all of it. Some writers get technical, most leave it vague.
• Slick. Omega self-lubrication. Standard fanon, standard in explicit scenes.
• Suppressants. Medication that flattens heats or ruts. The genre's best plot device, because a prescription can run out, get stolen, stop working, or be quietly abandoned.
• Scent blockers. Patches, gels or collars that hide scent output. What a character wears to pass as a beta at work.
• Scent-blind. A character who cannot detect scent. Uncommon and useful, since it strips out the genre's shortcut and forces people to say things out loud.

Bonding

• Mating bond / mate bond. The permanent link formed between two characters. Depending on the writer it is emotional, empathic, or something closer to telepathy. Agree which version you are running before you form one.
• Mate bite / claiming bite / bonding bite. The bite at the scent gland that seals a bond. Usually written as irreversible, sometimes as fading, occasionally as breakable at a cost.
• Mating mark. The visible scar it leaves. Public information in a world where everyone can read it.
• Unbonded. Unclaimed and available, and in many settings socially conspicuous. A very common self-description in pitches.
• True mates / fated mates. The idea that two specific people are biologically matched, recognisable on first scent. Divisive: some writers build whole plots on it, others consider it a shortcut past the part of the story worth writing.
• Courting. The pre-bond phase. Gifts, nesting materials, scenting, permission asked and granted. Where slow burn lives.
• Bond sickness. The withdrawal a character suffers when separated from a mate or after a bond breaks. Angst fuel.

Social structure

• Pack. A group bonded socially rather than as a pair, from three people to a large found family. Packs turn a duet into an ensemble and are where multi-writer scenes happen.
• Pack alpha. The one at the top of it. Authority in the story, not a personality type.
• Nest. A built space of blankets, pillows and borrowed clothing, usually made by an omega, usually smelling of the people allowed in it. Being invited into someone's nest is a bigger moment than most sex scenes.
• Nesting. The act of building and defending one. Escalates before a heat.
• Alpha voice / command. A tone an alpha can use that an omega has trouble refusing. Powerful and easy to abuse in a scene, which is precisely why it should be negotiated up front like any other control mechanic.
• Presented society / omegaverse AU. Shorthand for the setting itself: a world where all of this is public, legal and ordinary. The alternative is a hidden-world version where only some people know.
• Mpreg. Male pregnancy, a frequent companion tag rather than a requirement. Divisive enough that it belongs in your pitch either way. Covered on its own at mpreg roleplay chat.

Tags, and the RP grammar around them

Half the vocabulary in a pitch is not omegaverse at all, it is general roleplay shorthand. The short version:

• IC / OOC. In-character and out-of-character. OOC goes in brackets, always, so nobody mistakes a question for a line of story.
• ERP. Erotic roleplay. What most of this room is doing.
• Para / multi-para / lit. Post length, from one paragraph a turn up to several. Match your partner's length; it is the clearest courtesy in the hobby.
• AU. Alternate universe. Omegaverse is itself an AU, and it stacks: coffee shop A/B/O AU, hockey A/B/O AU, and so on.
• Canon vs OC. Borrowed characters from a series versus your own inventions. Both are standard here, and a lot of A/B/O started as canon fic before people brought the framework to original casts.
• Dubcon. Dubious consent, the tag that covers most heat and rut plots. State it, negotiate it, and set a stop word before you write it.
• Squick / DNW. What you do not want. Borrowed from fic exchange culture and used the same way here.

The wider set lives in the roleplay glossary, and if a pitch drops kink vocabulary you do not recognise, the BDSM glossary covers that half.

Now go write something

The vocabulary is only worth having because it makes a pitch readable in three seconds. Omegaverse roleplay chat covers what actually gets played and how to pitch it, how to roleplay covers running the scene, and a lot of these writers cross over from anime roleplay. The room is free, anonymous and open at every hour.

Related: omegaverse roleplay · mpreg roleplay · roleplay glossary · BDSM glossary · how to roleplay

By LewdChat Editorial · Published September 1, 2026 · Last updated September 1, 2026