Things that are homologous can be defined as things that are similar. The word "Homologous" means; corresponding to or very much similar in position, structure, value or function. For instance scales of a fish are homologous to the feathers of a bird.
It has other more specific meanings as well, for instance in Genetics it refers to the gene loci of different chromosomes having the same linear sequence and morphology. In biology it refers to similarities that are found in evolutionary origin and structure but not in functionality, for instance the legs of humans and apes. In Immunology it relates to the correspondence between an antibody that is produced in response to an antigen and the antigen. In chemistry it is used to refer to a series of organic compounds, which differ from their preceding members at a constant incremental pattern, particularly by the addition of a CH2 group.
It has other more specific meanings as well, for instance in Genetics it refers to the gene loci of different chromosomes having the same linear sequence and morphology. In biology it refers to similarities that are found in evolutionary origin and structure but not in functionality, for instance the legs of humans and apes. In Immunology it relates to the correspondence between an antibody that is produced in response to an antigen and the antigen. In chemistry it is used to refer to a series of organic compounds, which differ from their preceding members at a constant incremental pattern, particularly by the addition of a CH2 group.
