Definition of merrow in English:

merrow

Pronunciation /ˈmɛrəʊ/

noun

Irish
  • A mermaid or a merman.

Origin

Early 19th century; earliest use found in Thomas Croker (1798–1854), antiquary. From Irish muruach, murúch from Early Irish murdúchann siren from muir sea + dúchann song, melody (further etymology unknown).