Earning a permanent place in the memory; memorable: an unforgettable experience. (adjective)
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 "unforgettable" in a sentence
"I'll keep a list of these things - of the things that people have said that they are looking for in a book they would describe as "unforgettable" - next to my computer, so that I can see them while I write, so that I can be reminded of what I am reaching for."
"When recalling unforgettable characters, three films quickly come to mind."
"This fabled location, best-known as the unforgettable exterior of William Castle's original HOUSE ON HAUNTED HILL 1959, has been suffering some signs of age and erosion in recent years, but we found it everything we ever hoped it would be."