1. Literally, to raise or tilt the brim of one's hat as a salutation, greeting, or mark of respect. It would be nice to live in a time when folks would tip their hats to you when you entered a room. When her father tipped his hat to me, I knew that he had come to accept me as part of the family.

2. To give one credit or praise for something. I really have to tip my hat to everyone who volunteered and made this such a success.