Origami symbols are a type of language between folders. Most folders could look at a diagram of a model, and fold it without looking at the text. (No-folders might find it strange, since you are just looking at the diagrams.) In fact, some people even look through the diagrams before folding. I also like to do that, since you will be prepared, and you can even fold the model in your head first.

Akira Yoshizawa created a set of origami symbols during the mid-20th centuary. Before that, diagrams were usually along the lines of  "fold point A to Point B. Now, lift up point C and push point X down." (could you guess what the folder is expected to do? If yes, please e-mail me the answer and write the subject as "solution to chalenge from symbols page".) There were also no names for folds and bases. Yoshizawa, Honda, and Robet Habin came up with names for the traditional bases, but people may call them by different names nowadays. I will continue this topic later on.

However, after the developement of folds, the symbols were not enough, and they represented dferent folds. People like John Montroll invented newer symbols, but people still use different symbols an names for folds and bases. More information are on obet Lang's diagramming page.