What is the defference between critical and crucial?

Answer 1

Crucial is used in formal contexts to mean 'decisive, critical': : the testimony of the only eyewitness was crucial to the case. Its broader use to mean 'very important' should be restricted to informal contexts: : it is crucial to get good light for your photographs.

In any emergency or crisis situation, there is usually a turning point. Such an event is called critical if it determines the outcome of a situation (: a critical point in the nuclear disarmament negotiations;: a critical election for the Democratic Party).

Crucial can also refer to a turning point, but it emphasizes the necessity of something happening before a result can be achieved (: the battle was crucial to their victory), while critical suggests more of a balance between positive and negative outcomes (: a critical debate on foreign policy).