one-to-one

one-to-one (comparative more one-to-one, superlative most one-to-one)

1. Matching each member of one set with exactly one member of another set.

   There is a one-to-one relationship between days with large cash shortages and his workdays.

2. (chiefly UK) Involving direct communication between two people.

   a one-to-one discussion

   a one-to-one teaching session

3. (mathematics, of a function) Injective, being an injection: having the property that no two elements of the domain are mapped to the same image.

• (involving direct communication): one-on-one (North America)

• one-to-many, many-to-one, many-to-many
• onto

• face-to-face
• man-to-man
• peer-to-peer

one-to-one (plural one-to-ones)

1. A personal relationship between two people.

• (personal relationship between two people): 121, 1-2-1