In professional wrestling, heat can refer to both crowd reactions and real-life animosity between those involved in a professional wrestling angle, or match. In terms of crowd reaction, heat is usually used to denote how much of a reaction a heel wrestler receives, but can also be used for a babyface. Although the term can in some contexts refer to either positive or negative crowd reactions, heat is usually used specifically to mean a negative crowd response (e.g. booing), with its opposite being a "pop" or positive reaction (cheering, clapping, etc.).