OF THE GREATEST AGE' The term 'Of the Greatest Age' is composed of two words, 'ELDEST' and 'Of the Greatest Age'. The word 'ELDEST' is a six-letter word meaning the oldest in a group or family. It is often used to refer to the oldest member of a family or group, or to describe something that has been around for a long time. The phrase 'Of the Greatest Age' is often used to refer to a period of time that was particularly significant or influential. It can also be used to refer to a person or thing that is considered to be the best or most important of its kind.