Tetrade

Tetrad ('group of 4') or tetrade may refer to: Tetrad (area), an area 2 km x 2 km square Tetrad (astronomy), four total lunar eclipses within two years Tetrad (chromosomal formation) Tetrad (general relativity), or frame field Tetrad formalism, an approach to general relativity Tetrad (geometry puzzle), a set of four simply connected disjoint planar regions in the plane Tetrad (meiosis), the four cells produced by meiotic cell division Tetrad (music), a set of four notes Tetrad (symbol), or tetractys, a triangular figure of ten points arranged in four rows, and mystical symbol Medical tetrad, a group of four signs or symptoms which characterise a specific medical condition Nibble, or tetrade, a 4-bit group a tuple of length 4 Tetrad Islands, in the Antarctic

== See also ==