(plə-nŏm′ĭ-tər, plā-)
A flat metal plate for gauging the accuracy of a plane surface in precision metalworking. Also called surface plate.

pla·nom′e·try n.
References in periodicals archive ?
He instructed "in Latin, Greek, Hebrew, the Grecian and Roman Histories and Antiquities...reading, writing, arithmetic- vulgar, decimal, and duodecimal-geometry, planometry, trigonometry, surveying, gauging, Italian bookkeeping, navigation and the proportions of the horizontal dials."