That's not surprising. It's a site for home-schoolers (for kids, which means it's my level too!). I know it isn't the authority on the subject, but basically there are a s@&%load of words there, and they're defined at a very basic level (again for kids, which is probably why the definitions are sometimes wrong/vague/outdated).
But I'm gonna go back and fix stuff later--just trying to get the words in now and then re-sort the lists, etc. as I read more sources. Thanks for posting corrections as you find them!