The term 'prefix meaning 'six'' can be solved by the word 'HEXA, ' which is a four-letter word. The prefix 'hexa' comes from the Greek word for six, which is 'HEX.' This prefix is used in many words to indicate that something has six parts or is related to the number six. For example, a hexagon is a shape with six sides, and a hexadecimal system is a numerical system based on the number sixteen.