星座
せいざ · seiza · JLPT N1 · noun
configuration
⭐ 星 = star, 座 = seat: stars sitting together in one seat make a constellation
The 座 here is the same as in 座席 (seat). Think of a constellation as a fixed group of stars that sits together in one spot of the night sky.
座 — 广 (shelter) + 坐 (to sit)
Originally written as 坐, meaning 'to sit' (two people 人人 sitting on the ground 土). The shelter radical 广 was added to specify the place where one sits — a seat, throne, or platform. 坐 remained the verb 'to sit,' while 座 became the noun 'seat.'