I. ˌkwä-drə-ˈvā-lənt, in sense 2 kwä-ˈdri-və-lənt adjective
Etymology: International Scientific Vocabulary
Date: 1865
1. : tetravalent
2. : composed of four homologous chromosomes synapsed in meiotic prophase
II. noun
Date: 1923
: a quadrivalent chromosomal group