Simon, utor uti usus sum is one of those verbs it's worth your while to wade through a large dictionary article on. "Use" doesn't do justice to it, any more than 'obtain' is a representative synonym for 'get' in English.
You can read the Lewis and Short article several places online. I like:
http://www.lib.uchicago.edu/efts/PERSEUS/Reference/lewisands...
Because it seems to load faster than the Perseus sites do.
Cheers, Stephen