from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A typically two-note whistle made as an often unsolicited expression of sexual attention.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A whistle, of two notes, to signify sexual interest in someone.
- v. To whistle in appreciation or sexual interest.
Sorry, no etymologies found.
As women we figure out that two-legged mammals that wolf whistle as you walk by are allyou get the picture.