tetrad

tet·rad  (ttrd)

n.

1. A group or set of four.

2. A tetravalent atom, radical, or element.

3. Biology

a. A four-part structure that forms during the prophase of meiosis and consists of two homologous chromosomes, each composed of two sister chromatids.

b. Botany A group of four cells, as of spores or pollen grains, formed by division of one mother cell.

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[Greek tetras, tetrad-; see k^wetwer- in Indo-European roots.]

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te·tradic adj.

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tetrad

Noun

a group or series of four [Greek tetras]

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tetrad  (ttrd)

1. A four-part structure that forms during prophase I of meiosis and consists of two homologous chromosomes, each composed of two identical chromatids. During prophase I of meiosis, one chromosome exchanges corresponding segments of genetic material with the other chromosome in the tetrad in the process called crossing over. See more at meiosis.

2. A group of four cells, as of spores or pollen grains, formed from a parent cell by meiosis. As part of the process of spermatogenesis, a spermatocyte divides into a tetrad of four spermatids, cells which go on to develop into sperm. See more at spermatogenesis.

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Tetrad a group of four; four things regarded together as a single object or thought.

Example: Great Tetrad of senior wranglers, 1898.

Thesaurus

Noun

1.

tetrad - the cardinal number that is the sum of three and one IV, Little Joe, quadruplet, quartet, quatern, 4, four, quaternion, quaternity, foursome, quaternary digit, figure - one of the elements that collectively form a system of numeration; "0 and 1 are digits"