Occurring at a relatively large but unspecified position in a series.
Occurring at position n in a sequence.
The item at position n in a sequence.
The item in a relatively large but unspecified position in a series.
Not known; unidentified; not well known.
A variable (usually x, y or z) whose value is to be found.
A person of no identity; a nonentity
Any thing, place, or situation about which nothing is known; an unknown fact or piece of information.