any small hardish rounded mass, e.g. an abnormal aggregation of cells in the body
a small rounded lump of a mineral or mineral aggregate
a swelling on the root of a leguminous plant, e.g. clover, containing symbiotic bacteria that convert atmospheric nitrogen into a form in which it can be used by the plant
nodular adj
nodulated adj
nodulation /-ʹlaysh(ə)n/ noun
[Latin nodulus, dimin. of nodus knot, node]