The First Battle of Bull Run is considered a key battle during the Civil War.
Which of the following is the definition of "key" in this context?

Question

Quizplus · Accepted Answer

The correct definition of the word is "of crucial importance, significant", as it highlights how essential this battle was for the development of the war.
"One of the buttons on a keyboard" is not the correct definition in this context.
"The principal tonality on a piece of music" is not the correct definition in this context.
"A metal instrument used to open and lock doors" is not the correct definition in this context.

The First Battle of Bull Run Is Considered a Key