"Don Dando" wrote in message news:r5_Nb.8413

.....Here's my cut at it: A motor is powered buy
electricity and an engine is the result of combustion.

I agree with you, basically, but here's a wrench to throw into it --

how do we categorize that thing referred to as a "hydraulic motor"?

What many friends and I arrived at over the years of trying to define all
the powered driving sources aboard large aircraft (combustion, electric,
hydraulic, pneumatic, etc.) is this: an internal or external combustion
engine converts a fuel (energy source) into an alternate energy form, and
that alternate energy form drives the mechanical device that converts the
energy to motion. A motor receives the driving energy form directly, and
uses it without further modification to drive the mechanical device that
converts the energy to motion. Thus, the thing that drives your car or boat
(gas or diesel), and the jet that powers a large aircraft, are all engines,
since they convert liquid fuel into air pressure, which ultimately drives
the device and converts to motion. An electric, hydraulic, or pneumatic
"motor" receives energy in a directly usable form, and converts to motion
without further change. Having said all that, the Europeans still refer to
motorcars, and motor sports, and huge numbers (perhaps a majority) of
Americans refer to that thing under the hood as their "motor".

JG