This standard presents definition of components in waveguide usage. These components are considered to be linear, passive, and reciprocal unless otherwise specified. The definitions included were drawn from the Institute of Radio Engineers document No.53 IRE 2.S1-1953, IRE Standards on Antennas and Waveguides; Definitions of Terms, No.59 IRE 2.S1-1959, IRE Standards on Antennas and Waveguides; Waveguide and Waveguide Component Measurements, International Electrotechnical Commission (IEC) documents, Technical Committee No.46, Cables, Wires, and Waveguides for Telecommunication Equipment, Waveguide Vocabulary Work, Category V, Junctions, and Category XIII, Waveguide Components and other sources. Some definitions are included unchanged, some have been modified or deleted, and several new definitions have been added.<>