- parameter
- 1656, from Mod.L. parameter (1631), from Gk. para- "beside, subsidiary" + metron "measure" (see meter (2)). A geometry term until 1920s when it yielded sense of "measurable factor which helps to define a particular system" (1927). Common modern meaning (infl. by perimeter) of "boundary, limit, characteristic factor" is from 1950s.