The Greeks called a place of public assembly agora; from this they built the word agoreuein, meaning speak, in the sense of addressing a public. When to this is added alias, meaning another, the compound gives us our "allegory," which is the speaking about one thing in the terms of something else.
In Masonry we have the allegory of Solomon's Temple, of a journey, of the legend of a builder, etc., in each case the acting and describing of one thing being intended to refer to some other thing. For example, the building of Solomon's Temple is described, not for the purpose of telling how that structure was erected, but to suggest men may work together in brotherliness at a common task.