Merrow

The Hiberno-English term merrow is an anglicisation of Irish murúch (with medieval attestations such as murdúchann / murdhúchu and related onomastic terms muirgeilt, samguba, suire). Medieval literature uses these terms in narratives of siren-like sea-nymphs encountered by legendary ancestors (Dindsenchas, Book of Invasions), while the popular image of merrows in English-language folklore was largely shaped by 19th-century collectors and writers (Croker, Keightley, Yeats). Those modern accounts blend older literary motifs (sea-song/siren) with folk narratives of sea–land marriage and a magical cap that mediates movement between realms.

Female merrows in the collected tradition are depicted as beautiful from the waist up with a lower body covered in greenish-tinted scales; they are said to have green hair which they groom with a comb and to show slight webbing between digits and a 'white and delicate film resembling the skin between egg and shell.' Male merrows are reported in some tales as grotesque, green-bodied figures. Descriptions vary between sources, and some transformational attributes are disputed or conflated with neighbouring seal-skin (selkie) motifs.

Merrows are sea-dwelling otherworld beings associated with song (the Middle Irish murdúchann etymology links them to 'sea-chant' or siren-like melody). They can interact intimately with humans: tales record courtship, intermarriage, and offspring, though merrows are said to eventually return to the sea. Movement between deep water and dry land is traditionally conditioned on possession of a magical cap (cochullín draíochta / cohuleen druith) belonging to the merrow. Female merrows may lure men beneath the waves in some accounts; male merrows appear in narratives as entertainers of fishermen and, in later literary retellings, as keepers of souls — though some famous tales were partly literary inventions.