Definitions
1.NounAn instrument or contrivance to size articles, or to determine their size by a standard, or to separate and distribute them according to size.
2.NounAn instrument or tool for bringing anything to an exact size.
3.NounAn object used at the airport to test to see if a carry on or personal item is the correct size allowed by the airline.
4.NounAlternative form of sizar (“undergraduate who received an allowance”).