Adjective
(mathematics, logic, of a relationship between two sets) having the property that many elements of one set may be assigned by the relationship to one element in the other set, and that a given element in the first set can be assigned by only one member of the second set.
From many sources to a single recipient.
Traditional management structure consisted of a hierarchical tree of many-to-one communications (from subordinate to manager), with each manager often significantly filtering what he passed on to his manager.
A function f that is not injective is sometimes called many-to-one. Source: Internet
User threads may be executed by kernel threads in various ways (one-to-one, many-to-one, many-to-many). Source: Internet