horizontal branch



  • (written as Horizontal Branch)
    Zone of the Hertzsprung-Russell Diagram in which stars of globular clusters are found. The stars here are of about zero absolute magnitude but have spectral types from about A to G, including some main sequence stars and some which have left the main sequence.


  • A branch drain accepting waste products delivered to it vertically, by gravity, from one or more similar but usually smaller fixtures, and conducting them horizontally to the primary disposal drain.