Source Beautiful Redemption Kami Garcia page:280
context: John squared his shoulders.
In their words:
[ skwair ]
a rectangle having all four sides of equal length.
anything having this form or a form approximating it, as a city block, rectangular piece of candy, etc.
verb (used with object), squared, squar·ing.
to reduce to square, rectangular, or cubical form (often followed by off ):He squared off the log to make a timber for his house.
to mark out in one or more squares or rectangles.
verb (used without object),squared, squar·ing.
to accord or agree (often followed by with ):Your theory does not square with the facts.
to settle, even, or balance a matter, as by paying a bill, returning a favor, or tying a score.