noun / verb
whistle
WISS-ul/ˈwɪsl/
A high, clear sound made by forcing air through a narrow opening.
The woman produces a high, clear whistle by blowing through the metal mouthpiece.

Etymology
Old English hwistle named a pipe sounded by blowing. The noun later also named the sound produced by pursing the lips and blowing, connecting the instrument with a similar clear, breath-made sound.
In context
Then blow out and try to feel uh the air form a whistle between the tip of the tongue and the front teeth.
More examples
- She whistles a cheerful tune while washing the dishes.
- Wind whistles through a crack in the window.
- A loud whistle from the referee stops the game.
Forms
whistle · whistles · whistled · whistling
whistler noun — A person who makes whistling sounds.