Alpha and omega are two different concepts. Alpha and omega are the first and last letters of the Greek alphabet, respectively, and are used as a Christian symbol and title of Christ and God in the Book of Revelation. On the other hand, the Alpha/Beta/Omega (A/B/O) universe is a kink trope in fan fiction that follows the hierarchy of wolves, where some people have defined biological roles based on a hierarchical system. In this universe, Alphas are the highest rank/type, Betas are regular human beings or have a mix of Alpha and Omega traits, and Omegas are submissive and gentle. Omegas go into heats, increasing their fertility, and may need to have sex during this time. Male Omegas are often envisaged as being able to become pregnant via a uterus connected to the rectum, and Alphas can impregnate regardless of their main gender.

In summary, Alpha and Omega are the first and last letters of the Greek alphabet and are used as a Christian symbol and title of Christ and God in the Book of Revelation. On the other hand, the Alpha/Beta/Omega universe is a kink trope in fan fiction that follows the hierarchy of wolves, where some people have defined biological roles based on a hierarchical system.