- involving an extremely important decision or result; decisive; critical: a crucial experiment.
- severe; trying.
- of the form of a cross; cross-shaped.
Origin of crucial
SynonymsSee more synonyms on Thesaurus.com
- involving a final or supremely important decision or event; decisive; critical
- informal very important
- slang very good
Word Origin and History for cruciality
1706, "cross-shaped," from French crucial, a medical term for ligaments of the knee (which cross each other), from Latin crux (genitive crucis) "cross" (see cross (n.)). The meaning "decisive, critical" (1830) is extended from a logical term, Instantias Crucis, adopted by Francis Bacon (1620); the notion is of cross fingerboard signposts at forking roads, thus a requirement to choose.