Longman Dictionary of Contemporary English
first cousin
noun
EXAMPLES FROM CORPUS
▪ His first cousin, Mariano Rivera, is a Yankee.
Wiktionary
first cousin
n. 1 A child of a parent's sibling. A nephew or niece of a parent. 2 A person who shares common grandparents but not common parents.
WordNet
first cousin
n. the child of your aunt or uncle [syn: cousin, cousin-german, full cousin]