Is there a good place on the web that describes the basics and
terminology of piston engines?

None that I've found. I've learned a lot on the Lycoming site, although
their main purpose seems to be avoiding liability rather than educating
their customers.

Your A&P can be an excellent source of knowledge. My A&P has been
remarkably patient, explaining everything to me multiple times.

I've learned a lot here, too, but, again, it's hit and miss. If you find an
all-inclusive "engine website", please share it with us all.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"