Serving to explain, explicate, or elucidate; expositive; of or relating to exposition.(adjective)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "expository" in a sentence
"What strange power gives blog authors the ability to write a loose ramble and call it 'expository'?"
"But crossing that kind of barrier requires rhetorical tools that go beyond plain expository argument."
"Unfortunately, there have been an awful lot of books about World War II, and The Postmistress, while intelligent and well meaning, doesn’t ultimately have much new to add ... the dialogue lacks snap ... and [Blake] engages in expository overload that’s really not needed for such a well-known tale."