Typically that's an INDICATOR to,
you know, check your engine.
The Big Bang Theory Season 2, Episode 5
Hmm, they say it could be a potential
INDICATOR of life on other planets.
The Big Bang Theory Season 10, Episode 9
No, I have met Bert, isn't he an INDICATOR
of life on other planets?
The Big Bang Theory Season 10, Episode 9
which looks nothing like
a phenolphthalein INDICATOR
The Big Bang Theory Season 5, Episode 7