Definition of "clumping"

BMP-2 and BMP-4 also induce the expression of the neurotrophin receptor, TrkC, in cultured crest-derived cells and induce the cells to coalesce into ganglion-like clumpings.

2006, Patrizia Ferretti, Andrew Copp, Cheryll Tickle, Embryos, Genes and Birth Defects

Heavy backstair clumpings announce huge Ab, my negro paddler.

1916, Nash Buckingham, De Shootinest Gent'man