crux

The most important, central, or fundamental essence or elements of an issue, problem, or matter at hand. Thank you all for attending this staff meeting. Before we get to the crux of the matter, I'd like to assure each of you that your jobs are secure. Here's the crux of the matter, Bill. We feel like your performance has really been slipping recently.

Also, heart of the matter. The basic, central or critical point of an issue. For example, In this trial the bloodstains represent the crux of the matter, or We think the second clause is the heart of the matter. Although crux is Latin for "cross," in English it means "difficulty" or "puzzle," and it is from the latter that this expression is thought to be derived. The variant employs heart in the sense of "a vital part" (as it is in the body). The first term dates from the late 1800s, the variant from the early 1500s.

The essential, pivotal point of an issue. The word “crux” came into English from Latin unchanged except in meaning; in Latin crux means “cross,” specifically the kind used in crucifixions and other executions. The English word “crux,” on the other hand, also signifies a difficulty or puzzle. This meaning, some writers believe, stems from the crossing of the two lines that make up a cross, which is also called a knot or node, whence the transfer to a “knotty problem.” Songwriter John Lennon, of Beatles fame, punned on the cliché in The Fingeltoad Resort: “That seems to be the crutch of the matter.”