Noun

1. The sound made by something moving rapidly or by steam coming out of a small aperture
2. The act of whistling a tune
3. The act of signalling (e.g., summoning) by whistling or blowing a whistle

Verb

1. Make whistling sounds
2. Move with, or as with, a whistling sound
3. Utter or express by whistling
4. Move, send, or bring as if by whistling
5. Make a whining, ringing, or whistling sound
6. Give a signal by whistling