1. Any nerve ending or other sensory receptor that is specifically sensitive to heat or a rise in body temperature, or cold.
2. A sensory receptor, usually a nerve ending in the skin, that is stimulated by heat or cold.

Nerve endings that come in two varieties, cold receptors and warm receptors.

Also referred to as peripheral receptors although these include, besides cutaneous receptors, those in the mucosae or lubricating membranes lining an internal surface or an organ; such as, the alimentary (a tubular passage functioning in the digestion and absorption of food and the elimination of food residue, beginning at the mouth) respiratory (breathing), and genitourinary canals (relating to both the reproductive and excretory organs).