assume (v.)

early 15c., "to arrogate, take upon oneself," from Latin assumere, adsumere "to take up, take to oneself, take besides, obtain in addition," from ad "to, toward, up to" (see ad-) + sumere "to take," from sub "under" (see sub-) + emere "to take," from PIE root *em- "to take, distribute."

Meaning "to suppose, to take for granted without proof as the basis of argument" is first recorded 1590s; that of "to take or put on fictitiously" (an appearance, etc.) is from c. 1600. Related: Assumed; assuming. Early past participle was assumpt. In rhetorical usage, assume expresses what the assumer postulates, often as a confessed hypothesis; presume expresses what the presumer really believes. Middle English also had assumpten "to receive up into heaven" (especially of the Virgin Mary), from the Latin past participle.

Definitions of assume

assume (v.)
take to be the case or to be true; accept without verification or proof;
I assume his train was late
Synonyms: presume / take for granted
assume (v.)
take on titles, offices, duties, responsibilities;
When will the new President assume office?
Synonyms: adopt / take on / take over
assume (v.)
take on a certain form, attribute, or aspect;
She assumed strange manners
The gods assume human or animal form in these fables
Synonyms: acquire / adopt / take on / take
assume (v.)
take on as one's own the expenses or debts of another person;
Synonyms: bear / take over / accept
assume (v.)
occupy or take on;
He assumes the lotus position
Synonyms: take / strike / take up
assume (v.)
seize and take control without authority and possibly with force; take as one's right or possession;
He assumed to himself the right to fill all positions in the town
Synonyms: usurp / seize / take over / arrogate
assume (v.)
make a pretence of;
She assumed indifference, even though she was seething with anger
Synonyms: simulate / sham / feign
assume (v.)
take up someone's soul into heaven;
This is the day when Mary was assumed into heaven
assume (v.)
put clothing on one's body;
The queen assumed the stately robes
Synonyms: wear / put on / get into / don