1660s, from Late Latin acceptabilitas, from Latin acceptabilis "worthy of acceptance," from acceptare "take or receive willingly" (see accept). Acceptableness (1610s) is older.

late 14c., "to take what is offered; admit and agree to (a proposal, etc.)," from Old French accepter (14c.) or directly from Latin acceptare "take or receive willingly," frequentative of accipere "receive, get without effort," from ad "to" (see ad-) + capere "to take" (from PIE root *kap- "to grasp"). Related: Accepted; accepting.

"pertaining to accent," c. 1600, from Latin accentus (see accent (n.)) + -al (1). Related: Accentually; accentuality.

accentuate (v.) 1731, "pronounce with an accent," from Medieval Latin accentuatus, past participle of accentuare "to accent," from Latin accentus "song added to speech," from ad "to" (see ad-) + cantus "a singing," past participle of canere "to sing" (from PIE root *kan- "to sing"). Figurative meaning "emphasize, place an accent or emphasis on" is recorded from 1865.

late 14c., "particular mode of pronunciation," from Old French acent "accent" (13c.), from Latin accentus "song added to speech," from ad "to" (see ad-) + cantus "a singing," past participle of canere "to sing" (from PIE root *kan- "to sing"). The Latin word was a loan-translation of Greek prosōidia, from pros- "to" + ōidē "song," which apparently described the pitch scheme in Greek verse. The meaning "effort in utterance making one syllable stronger than another in pitch or stress" is attested from 1580s; as "mark or character used in writing to indicate accent," it is recorded by 1590s. The decorative-arts sense of "something that emphasizes or highlights" is from 1972.The soundest distinction perhaps is that "accent" refers to the habitual stress laid on a syllable in ordinary pronunciation ; "stress" to a syllable specially accented for this or that reason, logical, rhetorical, or prosodic purely. [George Saintsbury, "Historical Manual of English Prosody," 1914]

1610s, "a hastener," from Latin accelerator, agent noun from accelerare "to hasten; make haste" (see accelerate). Motor vehicle sense of "pedal which operates the throttle and thus modulates engine speed" is from 1900; particle physics sense is from 1931.