The word 'triplet' is a relatively modern English formation, entering the language in the 17th century. It is built upon the adjective 'triple', which itself descends from the Latin triplus, a combination of tri- (three) and -plus (fold). The French-derived diminutive suffix -et was appended to create a noun specifying a single, distinct unit within a set of three. This logical construction moved from the general concept of "threefold" to designate specific trios, most notably in reference to three siblings born together, while also extending to groups in music and other fields.

Structure: triple (threefold) + et (diminutive suffix) - triple: From Latin triplus (threefold), from tri- (three) + -plus (fold). Functions as the base element denoting the number three. - et: A diminutive suffix of French origin (from Latin -ittum), used to form nouns indicating a smaller or specific instance of the base.