The word "crux" refers to the most important or central point of a matter or issue. It signifies the heart of a problem, situation, or argument, which is crucial for understanding or resolving it. When someone mentions the "crux" of a discussion, they are highlighting the key element that needs attention or focus.
The word "crux" originates from Latin, where it means "cross" or "crossing." In its historical context, it referred to the instrument of execution (the cross) used in the crucifixion of Jesus Christ, which is how it came to symbolize something crucial or pivotal in various contexts.