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) In general relativity, a frame field (also called a tetrad or vierbein) is a set of four pointwise- orthonormal vector fields, one timelike and three spacelike, defined on a Lorentzian manifold that is physically interpreted as a model of spaceti ...

, 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) The tetractys (), or tetrad, or the tetractys of the decad is a triangular figure consisting of ten points arranged in four rows: one, two, three, and four points in each row, which is the geometrical representation of the fourth triangular numb ...

, 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 In computing, a nibble, or spelled nybble to match byte, is a unit of information that is an aggregation of four- bits; half of a byte/ octet. The unit is alternatively called nyble, nybl, half-byte or tetrade. In networking or telecommuni ...

, or tetrade, a 4-bit group * a

tuple In mathematics, a tuple is a finite sequence or ''ordered list'' of numbers or, more generally, mathematical objects, which are called the ''elements'' of the tuple. An -tuple is a tuple of elements, where is a non-negative integer. There is o ...

of length 4 * Tetrad Islands, in the Antarctic

See also