This Means This.

This Means This, This Means That: A User's Guide to Semiotics

Sign
-Signs are often thought to be composed of two inseparable elements: the signifier and the signified.
-Signs are always produced and consumed in the context of a specific society.
-Societies have two basic sources of signing: the first source is natural, while the second is conventional.

Symbol
-In semiotics, the term "symbol" is used in a special sense to mean literally any sign where there is an arbitrary relationship between signifier and signified.

Metaphor
-Objects, images, and texts can all be used to create metaphors. Metaphors link something familiar with something unfamiliar. They work by a process of transference.