tet·rad /ˈtɛˌtræd/
  四個,四個一組,四分染色體
  tet·rad /ˈtɛˌtræd/ 名詞
  四分體,四裂體,四聯症,四價元素,四分孢子,四聯體,四聯球菌,四合花粉
  tetrad
  四元群
  Tet·rad n.
  1. The number four; a collection of four things; a quaternion.
  2. Chem. A tetravalent or quadrivalent atom or radical; as, carbon is a tetrad.
  ◄ ►
  tetrad
       n : the cardinal number that is the sum of three and one [syn: four,
            4, IV, quatern, quaternion, quaternary, quaternity,
            quartet, quadruplet, foursome, Little Joe]