Gemination, the act of doubling or duplicating, has many synonyms that can be used interchangeably. One such synonym is duplication, which refers to the process of creating a second copy of something. Another synonym is repetition, which describes the act of doing something again and again. Another synonym for gemination is doubling, which means to increase or multiply by two. The word twinning also serves as a synonym to denote the process of producing two identical individuals. Meanwhile, another synonym is reduplication, which refers to the repetition of the same sound or syllable within a word or across different words. Overall, there are many suitable synonyms for the word gemination depending on the context.