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surfactant sur·fac·tant (sər-fāk'tənt, sûr'fāk'-)
A surface-active substance.
A substance composed of lipoprotein that is secreted by the alveolar cells of the lung and serves to maintain the stability of pulmonary tissue by reducing the surface tension of fluids that coat the lung.
substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties. In the dyeing of textiles, surface-active agents help the dye penetrate the fabric evenly. They are used to disperse aqueous suspensions of insoluble dyes and perfumes.