surfactant

1. (chemistry) A surface-active agent, or wetting agent, capable of reducing the surface tension of a liquid; typically organic compounds having a hydrophilic “head” and a hydrophobic “tail”.Examples: "Dr. Khorana added that this is especially true of cleansers that feature surfactants like sodium lauryl sulfate, as this class of ingredients can cause “dryness, irritation and eczema.”"Synonyms: tenside

2. (biochemistry) A lipoprotein in the tissues of the lung that reduces surface tension and permits more efficient gas transport.Examples: "It is conceivable that impairment of surfactant proteins is due to rheological and immunodefensive disorders of testis and epididymis or prostate."