IPA: /ˈhɛdˌlɒk/
KK: /ˈhɛdˌlɑk/
A type of hold used in wrestling where one person wraps their arm around the head of another person to control them.
The wrestler put his opponent in a headlock to gain an advantage during the match.
Headlock → The word is formed from "head" (from Old English "heafod", meaning the upper part of the body) and "lock" (from Old English "locc", meaning to enclose or fasten). A headlock is a hold that encloses or fastens around the head.
Think of the 'head' as the upper part of the body being 'enclosed' or 'fastened' by a 'lock' — that's what a headlock does.