What is a multivariate random variable?

A multivariate random variable is also a variable, which consists of two unknowns.

For example, if you throw a ball into a rectangular coordinate plane, the impact point of the ball is a random variable, which is represented by coordinates (x, y) and is a binary random variable.

Another example is the weather on a certain day, which consists of sunny days and windy days. It is a random variable, and it is a binary random variable, with (sunny, level 3) indicating sunny and level 3 wind. If you add temperature, it is a ternary random variable.