A type of top secret development of something, such as weapons. There is possible disregard for morals and opinions, particularly opinions.
Black projects are usually government-related, sometimes paid for by the Pentagon's "black budget".
"For example : the Aurora plane is a black project."
"Certain things like laser cannons and time machines really do exist! It's called 'black projects'."
Military projects used to cover lesser known Grey projects.
To cover up such Grey projects as ET research, the military hides them behind black projects. Congress thinks the money is going into the development of defense technology, but in reality, it is going to defense tech and ET research.