Approval signal is a term used to describe a gesture or action that conveys agreement or acceptance. The three crossword solutions for the term are NOD, OLE, and OKAY. NOD is a gesture made by nodding one's head up and down to indicate agreement or understanding. OLE is a Spanish word meaning 'HELLO' or 'WELCOME' and is often used as an expression of approval. OKAY is an English word used to express agreement or acceptance.