1853 as a type of machine to cut grass, from lawn (n.1) + mower. Originally pushed by hand or drawn by horses, later also powered by a motor.
Entries linking to lawn-mower
lawn n.1
"turf, stretch of grass," 1540s, laune "glade, open space in a forest or between woods," from Middle English launde (c. 1300), from Old French lande "heath, moor, barren land; clearing" (12c.), from Gaulish (compare Breton lann "heath"), or from a cognate Germanic word, from Proto-Germanic *landam-, source of English land (n.). The -d perhaps was mistaken for an affix and dropped. Sense of "grassy ground kept mowed" first recorded 1733. Lawn-tennis is from 1884.
mower n.
early 14c., "one who cuts grass with a scythe," agent noun from mow (v.). Mechanical sense is from 1852.