As a noun, it is a place where two parts meet or are fastened together, such as where bones connect in the body. As an adjective, it means shared by two or more people or groups.
From Old French “joint,” past participle of “joindre,” meaning “to join,” from Latin “iungere,” “to yoke, join together.” The noun originally meant a joining or connection point. The adjective sense grew naturally from the idea of things being joined or shared.
Every time you bend your knee or elbow, you’re using a literal joint—the meeting of bones. The same root shows up in “conjunction” and “junction,” all about things coming together. Even a “joint project” is just people becoming the moving parts of one bigger body of work.
Complete word intelligence in one call. Free tier — 50 lookups/day.