corner: the angle where two sides of a structure meet, and by extension the cornerstone set there and a leader who holds a people together like one
At its root this word names a corner: the outer angle of an altar, a roof, a wall, a city, or a street, and the fortified corner tower that guards a wall. Most of its uses are this plain, physical sense.
From the corner comes the cornerstone, the chief stone laid where two walls meet, the one that sets the line for the whole building. A handful of verses use the word for that stone, including the famous line about the stone the builders rejected becoming the head of the corner.
The same image then stretches to people. Just as a cornerstone anchors a building, a leader anchors a community, so the word can mean a chief or ruler, the one the rest of the people lean on. This is why one Hebrew word can be translated corner in one verse and chief in another.
The senses are held together by a single picture: the load-bearing corner. Whether it is a stone corner of a building or a human leader of a nation, the word points to the place where weight is carried and the structure holds.