TV series example of the word

The Big Bang Theory Season 7, Episode 15
they'll let you visit the engine room.

The Big Bang Theory Season 7, Episode 15
the conductor said if I come back to the engine room,

The Big Bang Theory Season 2, Episode 5
...of an internal-combustion engine...

The Big Bang Theory Season 2, Episode 14
...I pointed out the "check engine" light to you several months ago.

The Big Bang Theory Season 10, Episode 15
On the second day, a diesel engine.