Abstract: A lighting device, or LED lamp 10 is described with a base element 12 for electrical contacting and mechanical mounting and an LED arrangement 20 with at least one LED element 70. The LED arrangement 20 is spaced from the base element 12 along a longitudinal axis L. In order to provide a lighting device and a lighting arrangement with a matched optical and thermal design, i. e. where both effective heat dissipation and an advantageous light intensity distribution are achieved, a lower heat dissipating structure 24 is arranged between the base element 12 and the LED arrangement 20. The lower heat dissipating structure 24 comprises a plurality of planar heat dissipation elements 26 made out of a heat conducting material, shaped to have at a first longitudinal position along the longitudinal axis L a first extension in cross-section, and at a second longitudinal position a second extension in cross-section.