Given random variables X, Y, …, that are defined on a probability space, the joint probability distribution for X, Y, … is a probability distribution that gives the probability that each of X, Y, … falls in any particular range or discrete set of values specified for that variable.
en.wikipedia.org/wiki/Joint_probability_distribution
A joint probability distribution shows a probability distribution for two (or more) random variables.
statisticshowto.datasciencecentral.com/joint-probability-distribution