AAS is a three-letter acronym that may refer to: In science and mathematics: Angle-Angle-Side, a method for showing congruency between triangles. ASCII Adjust after Subtraction, an Intel 80x86 processor instruction; see Intel BCD opcodes Atomic absorption spectroscopy, a methodology of analytical chemistry Adaptive Antenna Systems (also known as beamforming) In academia: Asian American Studies, an academic discipline which studies the experience of people of Asian ancestry in America Associate in Applied Science(s), a degree/title conferred on students by a college, university, or professional school on completion of a program of study of two years; see associate's degree In transport: Apalapsili Airport (IATA airport code: AAS) in Apalapsili, Indonesia Taylor County Airport (IATA airport code: AAS) in Campbellsville, Kentucky, United States Automobile Association of Singapore, a member of the FIA For special-interest groups: American Antiquarian Socie ...more

AAS is the acronym for Atomic Absorption Spectrometry. This involves use of a sophisticated and costly instrument , called atomic absorption spectrometer. Many metals as well as other elements can be identified and concentration determined from minute quantity of the sample very accurately. The principle is a modification of the old flame photometry.