ETYM Greek blastema bud, sprout.
A mass of undifferentiated cells from with an organ or body part develops.

ETYM AS. blaest a puff of wind, a blowing; akin to Icel. blâstr, Old High Germ. blâst, and from a verb akin to Icel. blâsa to blow, Old High Germ. blâsan, Goth. blęsan. Related to Blow to eject air.
1. (Baseball) A long and hard-hit fly ball.
2. An explosion (as of dynamite).