1. (a.) Being a single unit, or entire being or thing, and no more; not multifold; single; individual.

2. (a.) 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. (a.) 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.

4. (a.) Closely bound together; undivided; united; constituting a whole.

5. (a.) Single in kind; the same; a common.

6. (a.) Single; unmarried.

7. (n.) A single unit; as, one is the base of all numbers.

8. (n.) A symbol representing a unit, as 1, or i.

9. (n.) A single person or thing.

10. (indef. pron.) Any person, indefinitely; a person or body; as, what one would have well done, one should do one's self.

11. (v. t.) To cause to become one; to gather into a single whole; to unite; to assimilate.

12. (n.) A suffix indicating that the substance, in the name of which it appears, is a ketone; as, acetone.

13. (n.) A termination indicating that the hydrocarbon to the name of which it is affixed belongs to the fourth series of hydrocarbons, or the third series of unsaturated hydrocarbons as, nonone.