The term homologous comes from the Greek 'homos' meaning same and 'logos' meaning relation. So, literally, it means having the same relation. To make that a little clearer, we can say it means having a similar relative position, structure, function or origin. However, that definition is still somewhat broad and ambiguous. The reason for this is because the term 'homologous' is used in several different fashions in biology. The individual definitions are more specific, but they are all derived from the idea of 'having the same relation.'
