/ Dictionary / Index E einsteinium: Meaning and Definition of Find definitions for: ein•stein•i•um Pronunciation: (īn-stī'nē-um), [key] — n. Chem., Physics. a transuranic element. Symbol: Es; at. no.: 99. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: einsteinium (Thesaurus) Einsteinian Einstein model Related Content Daily Word Quiz: cetacean Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language