Definition of the crux
: the most important part of something (such as a problem, issue, puzzle, etc.) —usually + of The crux of the matter is that people are afraid of change. It's taken a while to get to the crux of the problem, but I think I finally understand it.
Word by Word Definitions
: a puzzling or difficult problem : an unsolved question
: an essential point requiring resolution or resolving an outcome
: a main or central feature (as of an argument)
Seen and Heard
What made you want to look up the crux? Please tell us where you read or heard it (including the quote, if possible).