definition of
crucial

[1] #1 crucial a. [important] of extreme importance; vital to the resolution of a crisis; "a crucial moment in his career"; "a crucial election"; "a crucial issue for women". wn

[2] #2 crucial s. [all-important, all important, essential, of the essence] of the greatest importance; "the all-important subject of disarmament"; "crucial information"; "in chess cool nerves are of the essence". wn