1. Disposition to exhale or evaporate; the quality of being capable of evaporation; that property of a substance which disposes it to rise and float in the air, and thus to be dissipated; as the volatility of fluids. Ether is remarkable for its volatility. Many or most solid bodies are susceptible of volatility by the action of intense heat.

By the spirit of a plant we understand that pure elaborated oil, which by reason of its extreme volatility, exhales spontaneously, and in which the odor or smell consists.

2. Great sprightliness; levity; liveliness; whence, mutability of mind; fickleness; as the volatility of youth.