Gone by, as time can be described in three different ways: PAST (4 letters), AGO (3 letters), and elapsed (7 letters). The term 'gone by' is used to refer to a period of time that has passed or is no longer present. The word 'PAST' is often used to refer to a period of time that has already happened, while 'AGO' is used to refer to a period of time that has passed since a certain point in the PAST. Finally, 'elapsed' is used to describe a period of time that has passed between two points in time.