"dynamic link libraries" also known as dll's are a part of computer software (or set of executable [runable] components). Typical computer software is made by several software developers who segment their work into small units and put it into individual files. The work that only has the purpose of being a reference to the other parts is called a library. To explain how this works I will use a very simple example of a simple spell checker. The spell checker has to do a number of things in order to check the spelling of the document. 1. get the document, 2. seperate the document into words, 3. seperate the words into root words (split it up so it would be word[s]), 4. search the dictionary to see if the word is in the dictionary, 5. If the word is in the dictionary continue on, 6. If the word is not in the dictionary try to come up with suggestions, 7. list suggestions, 8. continue.
This program would most likely contain several dll's but the most elementry of them would be the one that acts as the parser. The parser would be reuseable for almost all languages, it would only need a different set of rules on how to parse. Since this would be reusable code it would make sense to have this as a dll so that anything that needs a parser can have it and use it.
Please contact me if you have further questions regarding dll.
Matt