blasto-

1.
a combining form meaning “bud, sprout,” “embryo,” “formative cells or cell layer,” used in the formation of compound words:
blastosphere.
Also, -blast.
Origin
< Greek, combining form of blastós a bud, sprout
British Dictionary definitions for blasto-

blasto-

combining form
1.
(in biology) indicating an embryo or bud or the process of budding: blastoderm
Word Origin
from Greek blastos; see -blast
Word Origin and History for blasto-

before vowels blast-, word-forming element used in scientific compounds to mean "germ, bud," from Greek blasto-, comb. form of blastos "sprout, germ," of unknown origin.

blasto- in Medicine

blasto- or blast-
pref.
Bud; germ; budding; germination: blastocyst.