1. a figure of speech in which a word or phrase is applied to an object or action to which it is not literally applicable.
When you have a website and you want to communicate something you need to create a metaphor. If you want to imply a journey or a cowboy theme or anything in between you need a metaphor to connect with your audience. I have seen too many people that do not understand the power of a metaphor. Do not mix up your metaphor , remain consistent from the language you use to to the images you use. Do not confuse your audience with mixed metaphors. Working on a project about a journey metaphor we had a web design that mixed the metaphor of old books with Dr. Who style videos and guess what people were very confused. Keep you metaphor consistent and you will have a better web experience.