Tee-hee Definition

tēhē
tee heed, tee heeing, tee hees, tee-hee
noun
A sound made in imitation of a giggle or titter.
American Heritage
An instance of giggling or tittering.
American Heritage
verb
To titter or snicker.
Webster's New World
interjection
(used to suggest the sound of) A titter or snicker.
Webster's New World
Alternative spelling of tee hee.
Wiktionary

(colloquial) A typographical representation of tittering or laughter.

Wiktionary