Carried interest is the percentage of fund profits the General Partners keep after returning LP capital and (in many funds) clearing a hurdle rate. The standard venture fund structure is '2 and 20', 2% annual management fee and 20% carry. Carry is usually subject to a 'European waterfall' (paid only after the entire fund is in profit) or an 'American waterfall' (paid deal by deal).
Carry is what gives VCs the same incentive as founders: both make life-changing money only on outsized winners. The mechanics of how carry vests, distributes, and accelerates inside a GP partnership are themselves complex.