"Let us know," initially (4)

I believe the answer is:

rsvp

(Other definitions for rsvp that I've seen before include "Brief request to acknowledge invitation" , "Brief notation to say, answer the invitation" , "Answer! (Fr.)" , "Please answer the invitation, monsieur" , "Answer the invitation briefly, please" .)

I've seen this clue in the L.A. Times Daily and the Newsday.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.