FIF'TIETH, adjective The ordinal of fifty; as the fiftieth part of a foot. This may be used elliptically, as a fiftieth of his goods, part being understood; or in this case, the word may be treated in grammars as a noun, admitting a plural, as two fiftieths.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI