A
surfactant which when present in small amounts facilitates the formation of a
foam, or enhances its
colloidal stability by inhibiting the
coalescence of bubbles.
Source:
PAC, 1972, 31, 577
(Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix
II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry)
on page 612