"Enterprise Value" is one of the legitimate measures of company size, and is defined as market capitalization + net debt.
You can think of this as equivalent to the size of the company because it would be the amount of money you'd need (roughly speaking) to buy the entire company outright.
Don't forget to subtract cash in the EV formula. Otherwise you could take out a gigantic loan and magically get bigger, when really all you've done is shuffle some money from debt into cash.
