apheresis (n.)

also aphaeresis, "suppression of a letter or syllable at the beginning of a word," 1610s, from Latin aphaeresis, a grammarians' use of Greek aphairesis "a taking away," from aphairein "to take away," from assimilated form of apo "from, off" (see apo-) + hairein "to take" (see heresy). Related: Apheretic.