Webster's Revised Unabridged Dictionary · 1913

Titter

Titter , transitive verb

[Probably of imitative origin.]

To laugh with the tongue striking against the root of the upper teeth; to laugh with restraint, or without much noise; to giggle.
A group of tittering pages ran before. — Longfellow

Titter , noun

A restrained laugh.
There was a titter of... delight on his countenance. — Coleridge

Titter , intransitive verb

To seesaw. See Teeter.