/ Dictionary / Index D decahydrate: Meaning and Definition of Find definitions for: dec•a•hy•drate Pronunciation: (dek"u-hī'drit, -drāt), [key] — n. Chem. a hydrate that contains ten molecules of water, as washing soda, NaCO&multiplydot;10HO. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. decahedron decahydronaphthalene Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language