(Homonym: cent, sent).
An odor left in passing by which a person or animal can be traced.

ETYM Old Eng. smel, smil, smul, smeol. Related to Smell.
Sense that responds to chemical molecules in the air. It works by having receptors for particular chemical groups, into which the airborne chemicals must fit to trigger a message to the brain.
A sense of smell is used to detect food and to communicate with other animals (see pheromone and scent gland). Aquatic animals can sense chemicals in water, but whether this sense should be described as “smell” or “taste” is debatable. See also nose.
1. The act of perceiving the odor of something; SYN. smelling.
2. The faculty of smell; SYN. sense of smell, olfaction, olfactory modality.
3. The sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form; SYN. odor, odour, olfactory sensation, olfactory perception.