Dendritic cell: A special type of immune cell that with threadlike tentacles that are found in tissues, such as the skin, and boosts immune responses by showing antigens on its surface to other cells of the immune system. A dendritic cell is a type of phagocyte and a type of antigen-presenting cell (APC). Both Langerhans cells, found in the skin and follicular dendritic cells, found in lymphoid tissues, are types of dendritic cells.