The word "ago" is a common adverb used in English language to indicate a time in the past. However, there are other synonymous expressions that can be used in its place to add variety to written or spoken language. These include words such as "earlier", "previously", "formerly", "in the past", "once", "before", "back then", "historically", "heretofore", "already", "back in time", "long ago", "since then", and "preceding". The use of these alternative expressions can help to avoid redundancy and deliver a more engaging experience for the reader or listener.