A hollow tube through which something passes. For example, a conduit via which cables are run.
A rapid and complete loss of electromagnetic skywave signals, due to substantially increased ionization in the ionosphere. This ionization is caused by increased solar noise, which itself is caused by solar storms. It may last from a few minutes to several hours. Also spelled radio fadeout. Also called fadeout, Dellinger fadeout, or Dellinger effect.
A laboratory which provides the equipment and conditions necessary for testing. Such a laboratory may be utilized to simulate most any given surroundings. Its abbreviation is test lab. Also called testing laboratory.