When the word assume was first used in English in a 1436 collection of poems, it referred to the the process of being received into Heaven, and a more specific sense of this still exists in some Christian theologies as the Assumption of the Virgin Mary. The first time it was used in the modern sense was in the 1590s, and it has increased in usage since then, peaking in the early 1970s. The word comes from the Latin word assumere, meaning "to take up" (the connection being the action of taking something for granted or taking up an opinion), from the prefix ad- ("to"; from PIE ad, with the same meaning), and the verb sumere, meaning "to take". Finally, sumere was composed of another prefix, sub- ("under"; from PIE upo, with the same meaning) and another verb meaning "take", emere (that's from PIE em, "to distribute").
Hello! I'm Adam Aleksic, a junior studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy trivia, politics, vexillology, geography, board games, conlanging, art history, and law.