Crux and Tangency

Crux noun - The central part or aspect of something under consideration.

Tangency and crux are semantically related In some cases you can use "Tangency" instead a noun "Crux".

Tangency noun - The state of being tangent; having contact at a single point or along a line without crossing.

Crux and tangency are semantically related in intersection topic. Sometimes you can use "Crux" instead a noun "Tangency".