mes·o·blast 
(mĕzə-blăst′, mĕs-)
(mĕzə-blăst′, mĕs-)n.
The middle germinal layer of an early embryo, consisting of undifferentiated cells destined to become the mesoderm.
mes′o·blastic adj.
- automatist
- automative
- automatization
- automatize
- automaton
- automatous
- automobile
- automobilist
- automotive
- autonomic
- autonomically
- autonomic nervous system
- autonomist
- autonomous
- autonomously
- autonomy
- autonym
- autopen
- autophagy
- autopilot
- autoplastic
- autoplastically
- autoplasty
- autopolyploid
- autopolyploidy