mermay is incorrectly written, and should be written as "Mermaid" being its meaning:
It is irregular or improper writing of the English word Mermaid siren means and which in turn has its origin from the French words mer ( mar ) and maid ( which is a contraction of the word mademoiselle for the English ) The sea girl. A mermaid is a legendary aquatic creature with the head and upper body of a human female and a fish tail. It is a mythical character that is very popular in all cultures of the world.