- Definite; fixed: set aside a certain sum each week. (adjective)
- Sure to come or happen; inevitable: certain success. (adjective)
- Established beyond doubt or question; indisputable: What is certain is that every effect must have a cause. (adjective)
- Capable of being relied on; dependable: a quick and certain remedy. (adjective)
- Having or showing confidence; assured. (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.