This standard provides a set of letter symbols for quantities and abbreviations and recommendations for their use in the science and technology of acoustics. The science and technology of acoustics includes sound@ ultrasound@ and infrasound in all media. Gases@ especially air; liquids@ especially water; and solids are examples of media with which acoustics is concerned. Specialties within acoustics that make use of the letter symbols and abbreviations within this standard include@ but are not limited to: speech@ hearing@ music@ noise control@ vibration@ shock@ sonar@ and transducers. Although remarks and limited short-form information are provided for many of the symbols and abbreviations contained herein@ definitions and methods of calculating the various quantities are outside the scope of this standard. Purpose To clarify the technical literature of acoustics by providing a standard set of letter symbols for use in mathematical formulations and a standard set of abbreviations for use in text@ especially in tabulations and on graphs; also to encourage the treatment of levels according to the standard rules for all quantities and units; and also to clarify the basic differences among quantity symbols@ unit symbols@ and abbreviations.