
I think it's CULTURAL.
The Big Bang Theory Season 11, Episode 10

Dude, can you even open your mouth
without spewing a CULTURAL stereotype?
The Big Bang Theory Season 4, Episode 9

We'd have
the same CULTURAL background...
The Big Bang Theory Season 1, Episode 2

...the CULTURAL convention
is to bring them hot beverages.
The Big Bang Theory Season 1, Episode 6

While you do provide
a certain CULTURAL diversity...
The Big Bang Theory Season 2, Episode 13