tract of level or undulating grassland in North America, by 1773, from French prairie "meadow, grassland," from Old French praerie "meadow, pastureland" (12c.), from Vulgar Latin *prataria, from Latin pratum "meadow," originally "a hollow." The word existed in Middle English as prayere, but was lost and reborrowed to describe the American plains. Prairie dog is attested from 1774; prairie schooner "immigrant's wagon" is from 1841. Illinois has been the Prairie State at least since 1861. In Latin, Neptunia prata was poetic for "the sea."