Meaning

noun a map showing planned or actual features of an area (streets and building lots etc.)

verb make a plat of

originFrom Middle English plat, plate, platte (“flat; smooth; blunt, plain”), from Anglo-Norman, Middle French, and Old French plat (“(adjective) flat, level; calm; blunt, plain; (adverb) in a flat position; directly, straight; bluntly, plainly”), from Vulgar Latin *plattus (“flat; smooth”); further etymology uncertain, but possibly from Ancient Greek πλατύς (platús, “flat; wide”), ultimately from…

Etymology from Wiktionary, CC BY-SA 3.0