fifteenth

Concise Oxford English Dictionary © 2008 Oxford University Press:
fifteen/fɪfˈtiːn/

▶cardinal number

• 1 equivalent to the product of three and five; one more than fourteen; 15. (Roman numeral: xv or XV)

• 2 a team of fifteen players, especially in rugby.

• 3 (15) Brit. (of a film) classified as suitable for people of 15 years and over.

• 4 (the Fifteen) the Jacobite rebellion of 1715.

– derivatives
fifteenth ordinal number.

– origin OE fīftēne, fīftīene (see five, -teen).