What is the meaning of the word "square"?

Definitions:

any artifact having a shape similar to a plane geometric figure with four equal sides and four right angles noun
- a checkerboard has 64 squares
be compatible with verb
- one idea squares with another
firmly and solidly adverb
- hit the ball squarely
having four equal sides and four right angles or forming a right angle adjective
- a square peg in a round hole
in a square shape adverb
- a squarely cut piece of paper
in a straight direct way adverb
- I looked you square in the eye.
pay someone and settle a debt verb
- I squared with him
position so as to be square verb
- You squared your shoulders.