assume

Assume is a verb with several closely related meanings centered on adopting a position, belief, or role for the sake of a process or action. The most common sense is to suppose something to be true for the purposes of argument, calculation, or planning. Another sense is to take on or undertake something, such as assume responsibility or assume a new role.

The noun form is assumption, which refers to a proposition accepted as true for the sake of argument, or to the act of assuming something in the sense of taking it on.

The word derives from Latin assumere, from ad- “to” + sumere “to take,” and entered English via Old French in the late medieval period. In logic and mathematics, an assumption is a hypothesis adopted to derive consequences, often subject to later justification or refutation. In everyday language, to assume can imply taking something as true without proof, which can be weaker than warranted. By contrast, to presume usually suggests a higher degree of likelihood based on evidence, while suppose is often used for neutral or hypothetical scenarios.

Common collocations include assume responsibility, assume control, assume an attitude, and assume the opposite. In legal and business contexts, to assume may mean to take on duties, liabilities, or ownership, as in assume liability or assume control.

See also: assumption, presumption, hypothesis, take on.