What does assume mean?
The verb "assume" has two principal uses in modern English. First, it means to accept or suppose that something is true without proof or confirmation: if you assume a train is late because it usually is, you are taking that conclusion on trust rather than evidence. Second, it means to take upon oneself — to begin performing a duty, adopting a role, or exercising power, as when someone assumes office or assumes responsibility for a project. A third, more literary sense describes adopting an outward appearance or manner, often one that is not genuine. The word is neutral in tone and appears everywhere from casual conversation to law, mathematics, and philosophy, where assumptions serve as stated premises for argument. Because acting on unverified assumptions can lead people astray, the word frequently carries a gentle note of caution: writers often advise readers to verify rather than assume. Its Latin root, meaning simply 'to take up,' also connects it to words like consume and resume.
verbTo suppose something to be true without proof, or to take on or adopt a role, duty, or appearance.
- To accept or suppose that something is true without verification.
- To take on, adopt, or begin to exercise a role, duty, power, or position.
- To adopt a particular appearance, manner, or quality (often feigned).
"I assume you've already read the report."
"Don't just assume the meeting is cancelled — check your calendar."
"She assumed the role of interim director until a permanent hire was made."
"Assume" famously breaks into 'ass of u and me' — but the word itself comes from Latin 'ad + sumere', literally 'to take up for oneself.'
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of assume
"Assume" derives from the Latin verb 'assumere', formed from 'ad-' (toward) plus 'sumere' (to take up or take on). It entered English from Latin via Old French around the fifteenth century, originally carrying religious meanings such as the Assumption of the Virgin Mary into heaven. Over time its senses broadened to include taking on roles and duties, and later the mental sense of supposing something without proof. It shares the Latin root 'sumere' with cognates such as 'consume', 'resume', and 'presume'.
Related word forms
How assume is actually used
Neutral register, common in both formal and everyday speech. In logic and mathematics it carries a technical sense of taking a proposition as a starting premise. When used about manner or appearance ('he assumed an air of indifference'), it often suggests pretence or affectation.
Easily confused with assume
'Assume' means to accept something as true without proof, while 'presume' implies a stronger basis of probability or confidence in the supposition.