Sigma

Wikipedia definition:
Sigma (/ˈsɪɡmə/ SIG-mə;1 uppercase Σ, lowercase σ, lowercase in word-final position ς; Greek: σίγμα) is the eighteenth letter of the Greek alphabet. In the system of Greek numerals, it has a value of 200. In general mathematics, uppercase Σ is used as an operator for summation. When used at the end of a letter-case word (one that does not use all caps), the final form (ς) is used. In Ὀδυσσεύς (Odysseus), for example, the two lowercase sigmas (σ) in the center of the name are distinct from the word-final sigma (ς) at the end. The Latin letter S derives from sigma while the Cyrillic letter Es derives from a lunate form of this letter.

Now the definition you've been waiting for:
Sigma has been coined as a term for the strongest male in a group.
What the sigma? Some know “sigma” as the 18th letter of the Greek alphabet but it's also teen slang for a cool dude. According to Know Your Meme, sigma is “referring to a supposed classification for men who are successful and popular, but also silent and rebellious.”

A sigma male is also the role after alpha male, which refers to a chad, while this one refers to sigma.

Example 1:
Person1: Erm, what the sigma?
Person2: *Reloads gun* I'm sorry. I have to do this. You've been consumed by the brainrot.

Example 2:

Person1: You're such a sigma.
Person2: Oh, thanks. What about you?
Person1: Oh, I'm probably just an alpha.