Find the word definition

Douglas Harper's Etymology Dictionary
yard-arm

also yardarm, 1550s, from yard (n.2) in the nautical sense (attested from Old English) + arm (n.1). In 19c. British naval custom, it was permissible to begin drinking when the sun was over the yard-arm.

Wiktionary
yard-arm

n. (alternative spelling of yardarm English)

Usage examples of "yard-arm".

I ran up the rigging like a cat, and went out at the topgallant yard-arm.

Ah, what an engagement we had, yard-arm to yard-arm, as Jack Tar would say!