The word "tripleton" is a rarely used term, but there are some synonyms that can be used instead. A common synonym is "triplet," which refers to a group of three things or people. Another synonym is "threesome," which has a similar definition to triplet but can also refer to a group of three people who engage in sexual activity together. "Trio" is another synonym that is commonly used, particularly when referring to a musical group composed of three instruments or singers. Lastly, "trinity" is a synonym that refers to a group of three things or people that are closely related or interconnected, often with spiritual or religious connotations.