Use your lexicon to collect terms that you find interesting and define them the way you think they are correct.
You haven't selected any facts for terms with this tag.
You can do so by going to a term page and ticking the checkbox next to a fact.
This is also possible without registering. If you want to save your lexicon permanently, register now.
Also, you could just go to the general free tag page to see all terms tagged with free.
If you were registered, you could export your lexicon as a widget.