/ Dictionary / Index O oceanarium: Meaning and Definition of Find definitions for: o•cea•nar•i•um Pronunciation: (ō"shu-nâr'ē-um), [key] — pl. -nar•i•ums, -nar•i•a a large saltwater aquarium for the display and observation of fish and other marine life. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ocean oceanaut 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