What is another word for "flatten"?

Roget's Thesaurus (1911) lists these synonyms for "flatten": accubation, accumbent, all, alluvial, area, azimuth, back, beam, billiard, board, bowling, butte, calm, couch, couchant, cricket, croquet, dead, decumbence, decumbency, decumbent, discoid, discumbency, down, esplanade, estrade, even, fell, flat, flatness, floor, flounder, fluke, flush, glass, green, ground, hand, horizontal, horizontality.