the.com/crowning

means The act of placing a crown on someone's head, or more broadly the high point or culmination of something; also the medical moment when a baby's head first becomes visible during birth.

from From the Old English 'corona'-borrowed-into-English path: 'crown' descends from Latin 'corona' (a wreath or garland), which entered Old English via Old French 'corone.' The Latin 'corona' is itself likely related to Greek 'korōnē,' meaning something curved or bent. The '-ing' simply turns the noun-verb 'crown' into the ongoing act. The obstetric sense — the head 'crowning' at the threshold — is a vivid borrowing of the same image: the head emerging like a crown coming into view.