Definition: Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.
Input: Question: Is there a semantic difference between engine and motor? In some cases, would the use of one or the other word be technically incorrect? 
Answer: I like the definitions provided by WordNet and their definition is the way I've understood the difference: A motor is a machine that converts other forms of energy into mechanical energy and so imparts motion. An engine is a motor that converts thermal energy to mechanical work. wordnetweb.princeton.edu So an engine is a specific type of motor. That's why it's not incorrect to speak of a motorboat, or a motorcar, or a motor speedway, even if the boat or car is clearly powered by combustion. Note that if there's no combustion, there's no engine. Purely electric cars don't have engines. As nouns, motor can also refer to a nonspecific agent that causes motion: "happiness is the aim of all men and the motor of all action", and engine can refer to something used to achieve a purpose: "an engine of change", a railway locomotive, or a machine used in warfare: "medieval engines of war".

yes