one

one is an Adverb

Definition:

[1] Being a single unit, or entire being or thing, and no more; not multifold; single; individual. The dream of Pharaoh is one. Gen. xli. 25. O that we now had here But one ten thousand of those men in England. Shak.

[2] Denoting a person or thing conceived or spoken of indefinitely; a certain. "I am the sister of one Claudio" [Shak.], that is, of a certain man named Claudio.

[3] Pointing out a contrast, or denoting a particular thing or person different from some other specified; -- used as a correlative adjective, with or without the. From the one side of heaven unto the other. Deut. iv. 32.

[4] Closely bound together; undivided; united; constituting a whole. The church is therefore one, though the members may be many. Bp. Pearson

[5] Single in kind; the same; a common. One plague was on you all, and on your lords. 1 Sam. vi. 4.

[6] Single; inmarried. [Obs.] Men may counsel a woman to be one. Chaucer.

[7] Referring to future time: At some uncertain day or period; some day. Well, I will marry one day. Shak.