Webster's Revised Unabridged Dictionary · 1913

Tilde

Tilde , noun

[Sp., from Latin titulus a superscription, title, token, sign. See Title, n.]

The accentual mark placed over n, and sometimes over l, in Spanish words [thus, ñ], indicating that, in pronunciation, the sound of the following vowel is to be preceded by that of the initial, or consonantal, y.