/ Dictionary / Index A accessorius: Meaning and Definition of Find definitions for: ac•ces•so•ri•us Pronunciation: (ak"su-sôr'ē-us, -sōr'-), [key] — pl. -so•ri•i any muscle, nerve, gland, etc., that reinforces the action of another. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. accessorial accessorize Related Content Daily Word Quiz: impetuous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language