"Yei" is a Navajo word that refers to a certain type of spirit or deity in their mythology. Synonyms for "yei" could include "kachina," which is another term for spirit beings in Pueblo and Hopi cultures. Another possible synonym is "tó," which refers to Navajo spirits that are believed to be helpers of medicine men and women. "Yei-bi-chai" is another synonym that specifically refers to a type of ceremonial dance that honors the yei spirits. Additionally, some may use "god" or "goddess" as a synonym for "yei," as the spirits are often revered and respected in a similar manner to deities in other religions.