tetrad
nounCA, US, UK /ˈtɛtɹæd/ · AU /ˈtetɹæd/
Etymology From Ancient Greek τετράς (tetrás), analysable as tetra- + -ad.
7 senses
- 1A group of four things.
- 2Two pairs of sister chromatids (a dyad pair) aligned in…
- 3A group of four haploid and immature pollen grains in…
- 4A unit of land area of two by two (that is, four) square…
- 5A tetravalent atom or radical.
- 6A group of four basis vectors for a four-dimensional…
- 7A chord comprised of four notes; a tetrachord.
A group of four things.
- Religious movements and cults are often founded on a tetrad of elements: a prophet, a prophecy, a book, and a revelation.2010, Siddhartha Mukherjee, The Emperor of All Maladies, Fourth Estate (2011), page 177:
Biology, Natural sciences Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.
Biology, Natural sciences A group of four haploid and immature pollen grains in tetrahedral fashion produced by meiotic microsporogenesis.
Cartography, Geography, Natural sciences A unit of land area of two by two (that is, four) square kilometres.
- They took figures for the abundance of invasive weeds mapped according to the normal grid unit of the 'hectad', or 10 × 10 km square, and then looked at how abundant these species were mapped at a much finer scale – in 'tetrads', or 2 × 2 km squares, inside these hectads.2010, Richard Mabey, Weeds: How Vagabond Plants Gatecrashed Civilisation and Changed the Way We Think about Nature, London: Profile Books, →ISBN:
Chemistry, Natural sciences, Physical sciences A tetravalent atom or radical.
Mathematics, Sciences A group of four basis vectors for a four-dimensional manifold in differential geometry.
Entertainment, Lifestyle, Music A chord comprised of four notes; a tetrachord.
- Derived terms
- bitetrad, intratetrad, tetradic, Tetradite, tetrad of Fallot