‘Nerds’ in the plural is used for a group of people whether they are nerds or not. Like ‘guys’ even if some of them are female.
A singular ‘nerd’ though is almost always used in reference to a ’smart’ type person.
↓ Transcript
Geezer: What's the difference between a nerd and a geek?
Kidd: A nerd knows math and science. Brainy stuff. And they are thin.
Kidd: A geek knows comics and movies. Pop culture. / Geezer: And you AIN'T thin.
Kidd: A nerd knows math and science. Brainy stuff. And they are thin.
Kidd: A geek knows comics and movies. Pop culture. / Geezer: And you AIN'T thin.

















