A diacritical mark ( ~ ) placed over the letter n in Spanish to indicate the palatal nasal sound (ny), as in cañon, or over a vowel in Portuguese to indicate nasalization, as in lã, pão.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "tilde" in a sentence
"The tilde is the ~, probably located at the upper left of your keyboard."
"Far too many people mistakenly refer to this key as the tilde (~) key because the tilde is the shifted character over the accent grave on standard US keyboards."
"It's called a tilde, and it lets you turn the gravity off."