This informal British meaning refers to one pound sterling and remains unchanged in the plural.
The ticket costs twenty quid.
He paid a few quid for the book.
This older meaning refers to a compact piece of tobacco or another substance kept in the mouth for chewing.
The sailor placed a quid of tobacco in his mouth.
He carried a small quid wrapped in paper.
In the Latin expression quid pro quo, quid forms part of a phrase meaning one thing exchanged for another.
They expected a quid pro quo for their support.
The arrangement involved a clear quid pro quo.
