What are homologous chromosomes? What happens to homologues during meiosis?

Homologous chromosomes are a set of one maternal and one paternal chromosome that has approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci.

In meiosis homologous chromosomes pair and allows crossing over of genetic material. This process is known as recombination. This genetic recombination is what produces the variation of genes.