The paired chromosomes are called bivalent or tetrad chromosomes.
成对的染色体称为二价体(也称为四分体)。
英语百科
Bivalent (genetics)
(重定向自Bivalent chromosome)
A bivalent, sometimes referred to as a tetrad, is the association of a pair of homologous chromosomes physically held together by at least one DNA crossover. This physical attachment allows for alignment and segregation of the homologous chromosomes in the first meiotic division.