Here are a couple of good resources for looking up legal definitions. This will be helpful for anyone putting together their contracts.
I am a big advocate of "plain English" contracts, but some legal terms are still necessary. Even if you use a contract template you should clearly understand the language in the contract and the "intent" behind it. Understanding a contracts language and intent is even more critical if you are on the receiving end of a contract provided by someone else.
law.com Law Dictionary
Glossary of Legal Terms