Groups of three is a term used to describe collections of three items or people. The most common words used to describe such groups are triunes, trios, trines, and triads. Triunes is a seven letter word meaning a group of three gods or goddesses in ancient mythology. Trios is a five letter word meaning a group of three people or things. Trines is a six letter word meaning a group of three related things or people. Lastly, triads is a six letter word meaning a group of three people or things that are closely related.