I perform a lot of blog reviews and give a lot of blog advice and often times I learn a great deal from the questions asked.  I've found a site called Apogee that hosts a Search Engine Optimization Glossary or SEO Glossary.

They have definitions for a lot of terms that come up in the course of blogging, web optimization, blog optimization, and even more.

Just to give an example, they provide definitions for some words that I've heard and understood in context but never had a solid definition:
Link Farm                  Long Tail Keywords               Made for Adsense (MFA)

Title Tag                    Cost Per Click                           Slurp
Note. These links would be an example of Deep Linking - also a word defined in their glossary.  So fi you get stumped in a message board somewhere, this would probably be a good resource to check on for a quick definition.