Scientific etymology and folk etymology.

Scientific etymology is the study of the origin and history of words, as well as the changes that have occurred in their meanings over time. It is based on the principles of linguistics and relies on evidence from a variety of sources, including written records, inscriptions, and linguistic reconstruction.

Folk etymology, on the other hand, is the process by which people attempt to explain the origin and meaning of words based on their own understanding and beliefs, rather than on evidence or analysis. Folk etymologies often involve the creation of new meanings or explanations for words that are not supported by linguistic evidence. For example, the folk etymology of the word “posh” is that it stands for “port out, starboard home,” supposedly because the best cabins on British ships sailing to India were on the port (left) side going out and the starboard (right) side coming home, to avoid the hottest part of the day. However, this explanation is not supported by linguistic evidence and is most likely a myth.