geminate

Geminate, from the Latin geminatus meaning twin, is an adjective and verb used to denote something that is paired or doubled. In linguistics, the term most often refers to a consonant that is longer in duration than a typical or singleton consonant, a phenomenon called gemination. The noun gemination describes the process or its result.

In phonology, gemination can be contrastive, meaning it can distinguish words within a language. Many languages have phonemic gemination, where words differ in consonant length rather than just place or manner of articulation. Representation varies by language: some use orthographic doubling of a letter (for example, Italian often marks gemination with a double consonant; Japanese uses a sokuon to indicate a geminate consonant in kana orthography). Phonetic realization of a geminated consonant typically involves a longer consonant closure, greater articulatory effort, and sometimes changes in timing, voice onset, or aspiration, depending on the language.

Outside linguistics, geminate appears in other fields with the sense of paired or twin entities. In chemistry and photochemistry, a geminate (or geminate pair) refers to two species produced together from a single event that remain associated long enough to recombine before diffusing apart; the process is called geminate recombination. In chemistry, the adjective geminal is more commonly used to describe substituents attached to the same atom, whereas geminate denotes the paired nature of the entities involved. The overarching idea across senses is the notion of two identical or paired parts.