noun

1. a mark (˜) used:
   1. in Spanish, over an n to indicate a palatal nasal sound (ny), as in señor
   2. in Portuguese, over a vowel or the first vowel of a diphthong to indicate nasalization, as in lã, pão
2. a similar mark used in some phonetic systems, to express negation in mathematics or logic, etc.

Etymology: Sp, metathetic var. of *title < L titulus, superscription, title