Mermaiden is a hyponym of merperson.
As nouns the difference between mermaiden and merperson
is that mermaiden is a mermaid, a maiden of the sea; siren while merperson is a mythological creature with a human upper half (head, arms, and torso) and a piscine lower half.
mermaiden
English
Noun
(
en noun)
a mermaid, a maiden of the sea; siren
Synonyms
* mergirl, merlady, mermaid, merwoman
merperson
English
Noun
(en-noun)
A mythological creature with a human upper half (head, arms, and torso) and a piscine lower half.
Hyponyms
* (female) mergirl, merlady, mermaid, mermaiden, merwoman
* (male) merboy, merguy, merlad, merman
* (parent) merfather, mermother
* (young) merbaby, merchild, merteen