From Longman Dictionary of Contemporary Englishtriplettrip‧let /ˈtrɪplɪt/ noun [countable] CHILDBABY/HAVE A BABYone of three children born at the same time to the same mother → twin
Examples from the Corpus
triplet• For example, many twins and triplets are born prematurely and suffer more physical problems related to low birthweight and undeveloped lungs.• I am a very proud Grandma of three boys - triplets - born last September.Origin triplet (1600-1700) triple + -et (as in doublet) 