What is the meaning of Crux?

The basic, central, or essential point or feature.

The critical or transitional moment or issue, a turning point.

A puzzle or difficulty.

The hardest point of a climb.

A cross on a coat of arms.

crucial or otherwise serious, difficult problem

crux (hardest point of a climb)

wooden frame on which criminals were crucified, especially a cross

gallows bird; one who deserves to be hanged

torture; misery

cross (symbol)

Source: wiktionary.org