Each chromosome pair contains genes for the same biological features, such as eye color, at the same locations (loci) on the chromosome.
Each chromosome pair can contain the same allele (both alleles for blue eyes) or different alleles (one allele for blue eyes and one allele for brown eyes) for each feature.
Non-homologous chromosomes representing all the biological features of an organism form a set, and the number of sets in a cell is called ploidy. In diploid organisms (most plants and animals), each member of a pair of homologous chromosomes is inherited from a different parent. But polyploid organisms have more than two homologous chromosomes.
Homologous chromosomes are similar in length, except for sex chromosomes in several taxa, where the X chromosome is considerably larger than the Y chromosome. These chromosomes share only small regions of homology.
Humans have 22 pairs of homologous non-sex chromosomes (called autosomes). Each member of a pair is inherited from one of their two parents. In addition, female humans have a homologous pair of sex chromosomes (2 X's); males have an X and a Y chromosome.
Homologous chromosomes are two pairs of sister chromatids that have gone through the process of crossing over and meiosis. In this process the homologous chromosomes cross over (not the sister chromatids) each other and exchange genetic information. This causes each final cell of meiosis to have genetic information from both parents, a mechanism for genetic variation. The homologous chromosomes are similar in length.
Homology of chromosomes is different from homology of genetic sequences, and predates that use of the term homology. An exception arises with allopolyploidy where chromosomes pair up by age, so sequence similarity is used to determine the original chromosomal sets.
Homologous chromosomes are also very similar to, and often confused with the term synteny (or gene homology)—which refers to genes located on the same section of chromosome between individuals of the same or different species.
See also a link from the synteny