T-square
From Longman Dictionary of Contemporary EnglishRelated topics: ToolsT-squareT-square /ˈtiː skweə $ -skwer/ noun [countable] AVDTZa large T-shaped piece of wood or plastic used to draw exact plans or picturesExamples from the CorpusT-square• Then, with a T-square positioned under the score mark, apply firm pressure to snap the glass.• And you had your instruments, your set squares and your T-squares and things.