system
Given the following post, respond as if you're commenting on Reddit:
human
Do black holes grow when they "absorb" matter?

I have no education at all In cosmology, but I've been reading a basic level book recently and if my understanding is correct, black holes are so massive that their gravitational pull causes matter (and even light?) to be "absorbed" (I imagine that's an incorrect term). Does the black hole "grow" when it absorbs matter then? 

Edit: Thanks for all the replies - clearly it's an area of cosmology/physics that interests a lot of other people too.
gpt
If you think of the size of a black hole as the radius of its event horizon, then yes. The radius of a black hole's event horizon, called the Schwarzschild radius, is 2GM/c^(2), where M is the mass of the black hole, G is the gravitational constant and c is the speed of light. As a black hole gains mass from things falling into it, its mass increases and so does its Schwarzschild radius.