1520s, "measured or prescribed size," altered from scantlon, scantiloun "dimension" (c.1400), earlier a type of mason's tool for measuring thickness (c.1300), a shortening of Old French escantillon (Modern French échantillon "sample pattern"), of uncertain origin; perhaps ultimately from Latin scandere "to climb" (see scan, v.). Sense influenced by scant. Meaning "small wooden beam" is 1660s. Related: Scantlings.