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 The purpose of this standard is 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. This standard also encourages the treatment of levels according to the standard rules for all quantities and units and clarifies the basic differences among quantity symbols@ unit symbols@ and abbreviations.