'great-nephew' definitions:

Definition of 'great-nephew'

From: WordNet
noun
A son of your niece or nephew [syn: great-nephew, grandnephew]

Definition of 'great-nephew'

From: GCIDE
  • great-nephew \great-nephew\ n. a son of a niece or nephew.
  • Syn: grandnephew. [WordNet 1.5]