IPA: /ˈlaɪnz.mən/
KK: /ˈlaɪnzˌmæn/
A person who officiates in sports, helping to monitor the game from the sidelines or court, and making calls about the ball's position or violations.
The linesman raised his flag to signal that the ball had gone out of bounds.
Linesman → It is formed from "line" (from Old French *ligne*, meaning a straight mark or boundary) and "-man" (meaning a person who). A linesman is a person associated with marking or maintaining lines, often in sports or technical contexts.
Think of a 'line' as a straight mark or boundary, and remember that a 'linesman' is a person who works with or oversees those lines.