Origins of “mermaid”
When did it first get used?
1200s as Old English “merewif”
1350ish as Middle English “meremayde”
What does it mean?
a fabled creature that has the top form of a woman and the bottom form of a fish; often causing harm to mortals whether intentionally or not; often magical or with supernatural qualities, as with a siren
What did it come from?
The first part is from mere, meaning sea, and maid, meaning woman. The 1200s Old English version is similar in its usage of mere but the wif ending reflects the word “wife” being used at the time to refer generally to women (rather than specifically to a married woman, as we have now).
What I thought was especially interesting here was that in Northern Europe, they didn’t actually have mermaids as having a fishy tail bottom half. I’m not clear on what they were instead, but apparently that was added through influence of sirens (magical creatures that sing to lure sailors to their death. Motivation varied. ;P)