Wiktionary
wetting agent
n. a substance, such as a surfactant, that reduces the surface tension of a liquid, allowing it to spread across, and penetrate the surface of a solid
WordNet
wetting agent
n. a substance capable of reducing the surface tension of a liquid in which it is dissolved [syn: wetter, surfactant, surface-active agent]
Usage examples of "wetting agent".
The addition of diesel fuel was partly to provide an additional element of chemical energy, but mainly to act as a wetting agent, the better for the internal shock wave to propagate within the explosive mass and hasten the detonation.
Unfortunately, the water washes away the wetting agent (the surfactant) in the lung air sacs (the alveoli) that helps keeps the sacs inflated.