Meaning:

“C” is short for “center” or “core,” and “位” means “position.” First used by gamers to refer to the position of the most prominent player in a team, this term is now more often used when referring to the center position in a photo, poster or stage performance attended by a group of people.

Example:

A: 漫威的海报谁站C位?

Mànwēi de hǎibào shuí zhàn C wèi?

Who normally stands at the center position in a Marvel poster?

B: 当然是钢铁侠小罗伯特·唐尼。

Dāngrán shì gāngtiěxiá xiǎo luóbótè táng ní。

Robert Downey Jr., who plays Iron Man, of course.