Frequency: The word is one of the 1500 most common words in English.
The ~ of a car or other vehicle is the part that produces the power which makes the vehicle move.
He got into the driving seat and started the ~.
...an ~ failure that forced a jetliner to crash-land in a field.
An ~ is also the large vehicle that pulls a railway train.
In 1941, the train would have been pulled by a steam ~.