Entry 1 sense Webster, 1913 crow's-nest /(krōz"nĕst`)/ · crow's·-nest · IPA 01 n. A box or platform near the top of a mast, esp. in whalers, to shelter the man on the lookout. 1. A box or platform near the top of a mast, esp. in whalers, to shelter the man on the lookout.(Naut.)