/ Dictionary / Index B blastosphere: Meaning and Definition of Find definitions for: blas•to•sphere Pronunciation: (blas'tu-sfēr"), [key] — n. Embryol. a blastula, esp. a blastocyst. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: blastosphere (Thesaurus) blastopore blastospore 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