From The Collaborative International Dictionary of English v.0.44 [gcide]:
bathtub \bath"tub\ n. A relatively large tub used to take a bath, usually a permanent fixture in a bathroom; it is an open container that is filled with water, in which a person immerses himself for the purpose of washing the body.
From WordNet (r) 2.0 [wn]:
From Moby Thesaurus II by Grady Ward, 1.0 [moby-thes]:
33 Moby Thesaurus words for "bathtub": aquamanile, automatic dishwasher, basin, bath, bidet, dishpan, dishwasher, ewer, finger bowl, kitchen sink, lavabo, lavatory, piscina, shower, shower bath, shower curtain, shower head, shower room, shower stall, showers, sink, tub, wash barrel, wash boiler, washbasin, washbowl, washdish, washer, washing machine, washing pot, washpot, washstand, washtub
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