- The definition of a nephew is a sibling's son or a sibling-in-law's male child.
An example of nephew is your sister's son.
- the son of one's brother or sister
- the son of one's brother-in-law or sister-in-law
- an illegitimate son, as of a medieval prelate: a euphemism
- a descendant
Origin of nephewMiddle English neveu ; from Old French ; from Classical Latin nepos ; from Indo-European base an unverified form nepot-, grandson, nephew from source Sanskrit napat, Old English nefa
A son of one's brother or sister or of the brother or sister of one's spouse.
Origin of nephewMiddle English neveu, nepheu, from Old French nevo, neveu, from Latin nepōs; see nepōt- in Indo-European roots.