How do you define "Marxism-Leninism"?

Would like to ask - what is a good, concise but full definition of Marxism-Leninism? Of course, I know what it is generally, but I am not sure how to convey it cleanly.

Generally I always want to mention that it's a science (i.e. what would you answer to "define fluid physics") so my go to is usually something like "In science, referring to the Marxist-Leninist branch of socio-economics" but I think it might extend a bit beyond that? Would like to ask your guys thoughts on it.