The term 'indefinite period' refers to a length of time that is not fixed or determined. It can be used to describe a long or short amount of time, and is often used when referring to a situation that is ongoing or has no end in sight. Two words that can be used to describe an indefinite period are 'WHILE' and 'EON'. WHILE is a five-letter word meaning 'during the time that' or 'at the same time as', WHILE EON is a three-letter word meaning 'an immeasurably long period of time'.