What do we call a pair of duplicated homologous chromosomes held together during meiosis?

A pair of duplicated homologous chromosomes that are held together during meiosis is referred to as a bivalent. This term specifically describes the structure that forms during prophase I of meiosis, where homologous chromosomes align closely together to facilitate crossing over and genetic recombination.

In this context, the bivalent consists of two homologous chromosomes, each made up of two sister chromatids, which are connected by chiasmata where exchanges of genetic material may occur. This is crucial for increasing genetic diversity in gametes.

The other terms provided are related but do not accurately describe the pair of homologous chromosomes in the context of meiosis. For example, chromatids are the individual strands of a chromosome that become visible during cell division, while a centromere is the region where sister chromatids are joined together within a single chromosome, and chromosome pair is a more general term that does not specifically refer to the formation seen during meiosis.