secretion
[C/U] Both
This term carries a clinical or biological weight, evoking the image of a controlled, specialized release of chemicals. It suggests a functional purpose, where a body part creates a specific fluid to serve a biological role, such as lubrication, digestion, or signaling.
Countable when referring to a specific type of substance, like a pheromone secretion. Uncountable when referring to the biological process of secreting.