Where does the term 'conspiracy theory' come from?

Was it really via the CIA in the 1960s in response to the JFK assassination?

Intro

I, like many of those seeking the truth, love a good conspiracy theory. Aliens, Bigfoot, the Illuminati - nothing is too wild for me to at least consider at this point.

The trick is to get to a level of knowledge where you know enough to then take right action in the world, but not going too far where literally everything is a conspiracy.