Chuuk — formerly Truk, Ruk, Hogoleu, Torres, Ugulat, an Lugulus — is an island group in the south western part of the Pacific Ocean. It comprises one of the four states of the Federated States of Micronesia (FSM), along with Kosrae, Pohnpei, and Yap. Chuuk is the most populous of the FSM's states. Geographically, Chuuk is also part of the larger Caroline Islands group. Chuuk means mountain in the Chuukese language and was known mainly as Truk (a mispronunciation of Ruk), until 1990.