While writing The Man in a Box, for the scenes with the gear race I’ve constantly been using the word engine to refer to my power-converting device in question, simply because I like this word better than ‘a motor’. I didn’t specify the design of the vehicle there, save for the mention that it has a powercell (a battery) instead of a power Core and doesn’t run on fuel — nothing in that world does — thus it’s probably either electric type or something else native to that civilization (it was irrelevant to the story). So for a couple of days I’ve been thinking about this one — an alien world, an alien planet, I surely can use any word I like, right?
So I began digging into the question of semantics and engineering, and as you guessed it, the opinions on the use are varied. But would the use of one over the other word be technically incorrect in my case?
From the Differencebetween.net — Difference Between Engine and Motor
A motor converts electrical energy into mechanical energy while an engine converts various other forms of energy to mechanical energy.
An engine is a mechanical device that uses a fuel source to create an output.
The word ‘engine’ is generally used to refer to a reciprocating engine (steam or internal combustion) while ‘motor’ is generally used to refer to a rotating device such as an electric motor.
An engine is made up of pistons and cylinders while a motor is made up of rotors and stators.
Ok… I need to think about that design after all. (I’m writing adult/erotic SF here, mind you. All those rotors and pistons… Mmm!)
Meanwhile, I’m trying other sources, like English Language & Usage Stack Exchange. This is a question and answer site for linguists, etymologists, and serious English language enthusiasts. Ok, sounds great, right? And someone there even asks the same question I did! Lucky!
Not. The same thing, all over.
But what about motor speedway, General Motors, NASA’s rocket motor? Electric my ass. Argh!
Someone well-versed in thermodynamics probably would say something like, an engine uses an internal power source to achieve work; a motor uses an external power source to achieve work. An engine may be referred to as a motor, since it does provide motive power. All motors are not engines, however. The term engine is usually applied to something that itself burns fuel to produce power.
It may be a good idea to look for the answers at MIT School of Engineering ‘Ask an Engineer’ webspace: as with almost any word, it all depends how far you go back in time for your definition…