one-to-one
noun
°A personal relationship, especially a sexual one, between two people.
°injection (a mapping which takes no two points in the preimage to the same point in the image) or a bijection.
adjective
°Matching each member of one set with a member of another set.
°Involving direct communication between two people. Used especially to refer to situations in which one person is teaching one other person.
synonyms: 121, 1-2-1, one-on-one