noun

• 1Surveying
  rare A point used in triangulation as a substitute for a preferred but inaccessible nearby station.

  Measurements taken from such points are typically adjusted so as to match those that would have been taken from the preferred point.

• 2A small facility or building equipped for a particular purpose, which serves an auxiliary or subsidiary role to that of a larger principal one.

• 3Specifically. A radio or television station or transmitter used to retransmit the signal of another station, so as to improve coverage or reception over a particular area.

• 4In senses relating to artificial satellites. . A space station orbiting a planet (now rare).

• 5An installation at which artificial satellites are monitored or controlled, or which is used for transmitting and receiving signals to and from satellites.

• 6A radio or television station whose broadcasts are transmitted via satellite.