A commonly used shortened form of surface active agent. Surfactants are compounds which reduce interfacial tension at the boundaries between gases, liquids and solid. They promote wetting and penetration of liquids into solids and act as a detergent, emulsifier, or dispersing agent. These include additives to a concrete mix to reduce the surface tension of the mixing water and facilitate wetting, penetrating, emulsifying, dispersing, solubilising, foaming, and frothing. Non-ionic surfactants, such as ethoxylated alkyl alcohols and akyl phenols, have been used as emulsifiers in acrylic emulsion paints. Synonyms: surface active agent; wetting agent; detergent; penetrant; emulsifier; penetrant; dispersing agent. Museum of Fine Arts, Boston (2000); RS Means Building Glossary (undated). [J. Cassar, R. de Angelis]