#1 yup
#2 honestly not sure what it measures, but maybe how big it is around. There are a ton of different sizes.
#3 .30 or .60 is the motor size in Cubic inches. Electric are usually rated like 300, 450 or 600 sized and is really a completely different rating scale all together.

http://www.heliguy.com/nexus/glossary.html

that should do it for ya =)