ASCII 91 and 93 (and hence U+005B and U+005D). Used in matching pairs to denote stage directions in a play or additions to a quotation. In programming languages with C-like syntax, square brackets typically enclose array subscripts. In mathematics, their most frequent use is to denote closed intervals of real numbers. On Urban Dictionary, because they're used for markup and there are no escape sequences, opening square brackets can never appear in the text of a definition.
The standard QWERTY keyboard makes square brackets easier to type than parentheses, which is pretty silly considering how much more common parentheses are.
by Subsequence February 16, 2010
Get the square bracketmug. "wow - what happened to your hair - oh I'm just kidding it looks good" - not really, you're goofing on a square - because it looks horrible.
by superhero75 August 25, 2010
Get the Goofing on a Squaremug. A term used when someone royally forgets something or when they Drop the Ball. Time Square in New York City on New Years Eve has a ball that drops to signify the entering of a new year.
"Dan was going to bring me a condom to the party but he Time Squared me, I had to settle for a blow job from that bitch."
by Calling You Out August 12, 2009
Get the Time Squaredmug. by AnAmazingPerson July 29, 2009
Get the BA Squaredmug. one with a job and no points against them, learns from friends screw-ups not being able to stick it to the man properly.
by that one wondering guy you kno August 17, 2008
Get the square bearmug. 
Jane: "Did you see what my mom posted about me on my Facebook wall? How embarrassing! That was supposed to be kept on the down low!"
John: "Sure did! She really went town square on you!"
John: "Sure did! She really went town square on you!"
by Sunology April 9, 2010
Get the Town squaremug.