one-to-one adjective 3noun 2forms 3 adjective3 •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. •(UK) Involving direct communication between two people. •Injective, being an injection: having the property that no two elements of the domain are mapped to the same image. noun2 •A personal relationship between two people. •A direct match or equivalent.And though [Jesse] Armstrong[…] continues his avoidance of easy one-to-ones, there’s more than a whiff of Elon Musk to Venis […]. — 2025 formsone-to-ones · more one-to-one · most one-to-one