A report is given on the IEEE Standard for VHDL waveform and vector exchange to support design and test verification (WAVES) Language Reference Manual. This standard is a formal notation intended for use in all phases of the development of electronic systems. Because it is both machine-readable and human-readable, it supports the verification and testing of hardware designs; the communication of hardware design and test verification data; and the maintenance, modification, and procurement of hardware systems. This standard provides the syntactic and semantic framework for the unambiguous expression and aggregation of digital test data and timing information necessary to completely describe a test or set of tests for a digital system. WAVES digital test data (stimulus and expected responses) is described at the logic level. Voltage and current values are not described by WAVES and are beyond the scope of this standard.