/ Dictionary / Index R rhomboideus: Meaning and Definition of Find definitions for: rhom•boi•de•us Pronunciation: (rom-boi'dē-us), [key] — pl. -de•i either of two back muscles that function to move the scapula. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. rhomboid rhombus Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language