one-on-one
🇺🇸
/ˌwʌn ɑːn ˈwʌn/
🇬🇧
/ˌwʌn ɒn ˈwʌn/
involving only two people
The teacher scheduled a one-on-one session with the student to discuss their progress.
corresponding exactly to another thing
The new system allows for a one-on-one mapping of old to new codes.