/ Dictionary / Index G gadolinium: Meaning and Definition of Find definitions for: gad•o•lin•i•um Pronunciation: (gad"l-in'ē-um), [key] — n. Chem. a rare-earth metallic element. Symbol: Gd; at. wt.: 157.25; at. no.: 64. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: gadolinium (Thesaurus) gadolinite gadroon Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language