Sentence:  In ASD, the <WSD>beta</WSD> also functions as a contrast, as Yuri is assumed to be a <WSD>beta</WSD> before his first heat reveals his omega status. 
Meaning of the word marked with <WSD> tags:  In omegaverse fan fiction, a person of a (usually secondary) gender/sex that mirrors the biology of a normal human, being free from the biological drives of alphas and omegas but generally capable of bonding and mating with either.