Lamp , in particular a lamp for street lighting, having - a lighting means , in particular an LED, having a main light emission direction , - a reflector for emitting light indirectly into the environment, which reflector is arranged in front of the lighting means in the main light emission direction , - a support for supporting the lighting means , which support is provided on the rear side of the lighting means with respect to the main light emission direction , and - a heat sink which extends between the support and the lighting means , wherein the heat sink has: ∘ a receiving side with which the lighting means is thermally coupled, ∘ a heat conducting structure which extends away from the receiving side in the opposite direction to the main light emission direction toward the support , ∘ a side wall which completely surrounds the heat conducting structure laterally on the outside circumferential side and which is designed as a reflector on the side facing away from the heat conducting structure in order to reflect the light reflected by the reflector which is arranged in front of the lighting means , wherein the side wall has at least one inlet opening and the receiving side has at least one outlet opening , which openings are fluidically connected to one another via a cooling channel (KK) formed by the heat conducting structure in order to dissipate heat, which is transferred from the lighting means into the heat conducting structure , by means of convection via the cooling channel (KK). - a lighting means , in particular an LED, having a main light emission direction , - a reflector for emitting light indirectly into the environment, which reflector is arranged in front of the lighting means in the main light emission direction , - a support for supporting the lighting means , which support is provided on the rear side of the lighting means with respect to the main light emission direction , and - a heat sink which extends between the support and the lighting means , wherein the heat sink has: ∘ a receiving side with which the lighting means is thermally coupled, ∘ a heat conducting structure which extends away from the receiving side in the opposite direction to the main light emission direction toward the support , ∘ a side wall which completely surrounds the heat conducting structure laterally on the outside circumferential side and which is designed as a reflector on the side facing away from the heat conducting structure in order to reflect the light reflected by the reflector which is arranged in front of the lighting means , wherein the side wall has at least one inlet opening and the receiving side has at least one outlet opening , which openings are fluidically connected to one another via a cooling channel (KK) formed by the heat conducting structure in order to dissipate heat, which is transferred from the lighting means into the heat conducting structure , by means of convection via the cooling channel (KK). ∘ a receiving side with which the lighting means is thermally coupled, ∘ a heat conducting structure which extends away from the receiving side in the opposite direction to the main light emission direction toward the support , ∘ a side wall which completely surrounds the heat conducting structure laterally on the outside circumferential side and which is designed as a reflector on the side facing away from the heat conducting structure in order to reflect the light reflected by the reflector which is arranged in front of the lighting means , <EOS>