It was originally written over a letter as a mark of abbreviation, but has since acquired a number of other uses as a diacritic mark or a character in its own right, and there are a number of Unicode characters for these different roles. In the latter capacity (especially in lexicography), the tilde or swung dash is used in dictionaries to indicate the omission of the entry word.
Sunday, August 22, 2010
The tilde is a grapheme with several uses. The name of the character comes from Spanish, from the Latin titulus meaning "title" or "superscription", though the term “tilde” has evolved in that language and now has a different meaning in linguistics.