In mathematics, a set is a collection of different things; the things are elements or members of the set and are typically mathematical objects: numbers, symbols, points in space, lines, other geometric shapes, variables, or other sets. A set may be finite or infinite.
1. To put in a specified position or arrangement; place: set a book on a table; set the photo next to the flowers. 2. a. To put into a specified state: set the prisoner at liberty; set the house ablaze; set the machine in motion. b. To cause to begin an action: The noise set the dog to barking.