What's Another Word for Thesaurus?

In class we had been studying about satellite repair stations, repair stations that generally function independently but are managed by a main repair station.  The two are separate entities but rely on one another.

Stella: What's a thesaurus?
Me: If we look up a word in a thesaurus it tells us other words with similar meanings.
Abbot: So it's a dictionary.
Me: Close.  A dictionary tells us the meaning, a thesaurus tells us other words with the same meaning.
Abbot: So it's a satellite dictionary.