surfactant
noun /sɜːˈfæktənt/
/sɜːrˈfæktənt/
[countable, uncountable]- (specialist) a substance that reduces the surface tension of a liquid, often forming bubbles in the liquid
- (medical) a substance that keeps the lungs working well to prevent breathing problems
Word Origin1950s: from surf(ace)-act(ive) + -ant.