Make sure the post is 'square' to the floor. [=make sure that there is a right angle where the post and the floor meet]
I'll go on the trip if I can 'square it with' my parents. [=if my parents will agree to let me go]
Here's the rest of the money. Now we're 'square'. [=now we don't owe each other anything]
(..) Dialogue: Marked=..,Default,NTP,!Effect,lt's obvious, isn't it? We've got\Nto play our way across the room. Dialogue: Marked=..,Default,NTP,!Effect,Alright. Harry, you take\Nthe empty bishop's square. Dialogue: Marked=..,Default,NTP,!Effect,Hermione, you'll be\Nthe queen-side castle. (..)2001 Harry Potter and the Sorcerer's Stone