tetradn.

英 'tetræd

中文n. 四个；四个一组；[生物] 四分染色体；四价元素

词根词源

tetrad (n.)"the number four, collection of four things," 1650s, from Greek tetras (comb. form tetrad-) "group of four, number four" (see tetra-).

关键词

tetrad