late 14c., "particular mode of pronunciation," from Middle French accent, from Old French acent (13c.), from Latin accentus "song added to speech," from ad- "to" (see ad-) + cantus "a singing," past participle of canere "to sing" (see chant (v.)). Loan-translation of Greek prosoidia, from pros- "to" + oide "song," which apparently described the pitch scheme in Greek verse. The decorating sense of "something that emphasizes or highlights" is from 1972.
"to pronounce with accent or stress," 1520s, from Middle French accenter, from Old French acenter, from accent (see accent (n.)). Related: Accented; accenting.