one · ​. the number 1 · ​. used in formal language or for emphasis before hundred, thousand, etc., or before a unit of measurement · ​. used for emphasis to mean ' ...

one · ​. used to avoid repeating a noun, when you are referring to somebody/something that has already been mentioned, or that the person you are speaking to ...

There are 69 meanings listed in OED's entry for the word one, 11 of which are labelled obsolete, and one of which is considered derogatory.

3used for emphasis to mean “a single” or “just one” There's only one thing we can do. 4a person or thing, especially when they are part of a group One of my ...

to be a person who enjoys something, or who does something often or well I've never been a great one for camping. See one in the Oxford Advanced Learner's ...

one-to-one · ​between two people only. a one-to-one meeting; Teachers do not have much time for one-to-one contact with their students. Topics Working lifec1.

(North American English) (also one-to-one especially in British English) [usually before noun] between two people only.

Definition of one-to-one adjective from the Oxford Advanced American Dictionary. one-to-one adjective [usually before noun] = one-on-one.

one-on-one adjective (also one-to-one) [usually before noun] between two people only Teachers do not have much time for one-to-one contact with their students.

1[uncountable] the most important or best person or thing We're number one in the used car business. · 2[uncountable, countable] the song or album (= collection ...