Evolution

The twentieth entry is o órgão análogo, and the adjective behind it is one English has quietly split in two. Here it does the older work: an analogous organ does the same job as another without descending from it, the insect wing beside the bird wing, alike because both have to move air and not because anything was handed down. That is « analogous », and it is the exact opposite of « homologous » one entry earlier, which is the distinction the whole subject rests on. Then there is the noun, and the noun has gone somewhere else entirely. « An analogue » in everyday English is either a counterpart — a chemical analogue of a known drug — or it is simply the word for not digital: analogue clocks, analogue recordings, an analogue signal. Nothing in that second family has anything to do with common descent, and it is the family a reader meets first. The spelling keeps the two apart on the page, which is worth knowing: the adjective is « analogous », the noun « analogue », and « analog » is the noun as American English writes it.