Real Dictionary

tenth
fraction: A tenth is one of ten equal parts of something.
ordinal number: The tenth item in a series is the one that you count as number ten.

tenth in American English
preceded by nine others in a series; 10th
the one following the ninth
adjective: next after ninth; being the ordinal number for ten
adverb: in the tenth place; tenthly
noun: one of ten equal parts, esp. of one (1⁄10)

tenth in British English
adjective: coming after the ninth in numbering or counting order, position, time, etc; being the ordinal number of ten: often written 10th
adverb: after the ninth person, position, event, etc
noun: one of 10 approximately equal parts of something
sentence connector: as the 10th point: linking what follows with the previous statements, as in a speech or argument