Alpha/Beta/Omega, sometimes called Alpha/Omega or Omegaverse, is a kink trope wherein some people have defined biological roles based on a hierarchical system, although wether the Dom/sub aspect is biological or social is up to the writer.The terms were borrowed from older behavior research on captive wolves that had been misappropriated by popular culture, but do not reflect current wolf behaviour research. Fanworks using this trope may involve werewolf, knotting, or other animalistic elements, or the characters may be otherwise purely human.
Alphas are the highest rank in the dominance hierarchy. In some stories, they may exhibit "dominant" behavior or have other temperamental quirks. They are able to impregnate Omegas. Male Alphas usually have a knot when aroused. In some works, female Alphas are also able to impregnate others; some will temporarily grow a penis to do so, or their vulva will permanently grow into one when they present.

Betas are subordinate to Alphas in the dominance hierarchy, but this element is absent from a lot of fanworks in practice. Betas are often presented as having "normal" human anatomy, with none of the special attributes of Alphas or Omegas. They may be the peacemakers between Alphas and Omegas. Depending on the story they may be able to impregnate Omegas, or even female alphas. In some fanworks Betas aren't present and the trope is known as Alpha/Omega; in others they take the role and functions of Omegas, and Omegas aren't present.

Omegas are the lowest rank in the dominance hierarchy. They can get pregnant and go into heat. Male Omegas are self-lubricating and have the ability to become pregnant, sometimes referred to as being bred or mated. Omegas are sometimes portrayed as the most fragile of the hierarchy, with frailer bodies and painful presentations. Some fanworks may present male omegas as especially subject to fertility issues, miscarriages, and difficult pregnancies.