tenth (adj., n.)

"next in order after the ninth; an ordinal numeral; being one of ten equal parts into which a whole is regarded as divided;" mid-12c., tenðe; see ten + -th (1). Replacing Old English teoða (West Saxon), teiða (Northumbrian), which is preserved in tithe. Compare Old Saxon tehando, Old Frisian tegotha, Dutch tiende, Old High German zehanto, German zehnte, Gothic taihunda. As a noun from c. 1200.

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Definitions of tenth from WordNet
tenth (n.)
a tenth part; one part in ten equal parts;
Synonyms: one-tenth / tenth part / ten percent
tenth (n.)
position ten in a countable series of things;
tenth (adj.)
coming next after the ninth and just before the eleventh in position;
Synonyms: th