/ Dictionary / Index B blasto-: Meaning and Definition of Find definitions for: blasto- Pronunciation: [key] a combining form meaning “bud, sprout,” “embryo,” “formative cells or cell layer,” used in the formation of compound words: blastosphere. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. blast lamp blastocoel 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