Definition of neoblast in US English:

neoblast

noun

  • 1Zoology. In a planarian or other worm: any of the large undifferentiated cells in various worms, especially planarian flatworms, whose division brings about the regeneration of lost portions of the body.

  • 2Geology. A crystalline grain in a rock, especially a metamorphic rock, that is of more recent formation than other grains in the rock.

Origin

Late 19th century. From neo- + -blast. Compare slightly earlier neoblastic.