I don’t know the formal definition, but let’s say a GP of a $100 million (fully capitalized) fund earns carried interest of 5%, so he’s entitled to $5 million. The money is kept in an account and the next year the fund loses 3%, or $3 million. The GP would then have to take $3 million out of his $5 million to pay back the LPs for their losses.
Disclaimer: I think this is the way this works from examples that I’ve worked through.