/ Dictionary / Index A actinochemistry: Meaning and Definition of Find definitions for: ac•tin•o•chem•is•try Pronunciation: (ak-tin"ō-kem'u-strē, ak"tu-nō-), [key] — n. the branch of chemistry dealing with actinism; photochemistry. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. actinobacillus actinodermatitis Related Content Daily Word Quiz: digression Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language