Here is the latest in a series of tips on usage and style shared by Mignon Fogarty, better known as the one and only Grammar Girl. One of Mignon's correspondents inquires about when setup should appear as a single, unbroken word, and when there should be a space or a hyphen between set and up.

Karen W. from Ottawa, Canada, sees set up, set-up, and setup used interchangeably and wonders if that's OK.

Setup as one word or with a hyphen (set-up) is a noun for naming things such as a place setting at a table or a trap for criminals.*

  • The crime boss walked right into the setup.
  • Make sure table five has a full setup.

Set up as two words is a verb phrase for describing actions such as putting things in order, arranging a date, creating a trap for someone.

  • The judges still had to set up the chess boards.
  • That snitch set up Billy Red Nose.
  • Lucy, known around town as "the matchmaker," loved to set up her friends.

* As with many compound words, different dictionaries give different advice. Some show the noun as a closed compound and others show it as a hyphenated compound. The verb form is always two words.