sixth
n.n. the number six in a series. You use it to describe something that comes after the fifth person or thing.
n. the ordinal number corresponding to the cardinal number six. Often functions as a determiner or a fraction representing one of six equal parts.
She finished in sixth place during the race.
The office is located on the sixth floor of the building, just past the elevators.
While the first five chapters establish the historical context, the sixth chapter introduces the primary argument regarding economic shifts in the late nineteenth century.
From earlier sixt, from Middle English sixte, from Old English siexta, from Proto-Germanic *sehstô. By surface analysis, six + -th (ordinal suffix).
When used as a fraction, it is a countable noun; as an ordinal, it typically functions as a determiner or adjective.