thumb|240px|right|Irish mermaid (bas-relief, [[Clonfert Cathedral).]]
thumb|Carving of mermaid (possibly with mirror), [[Clontuskert Abbey]]
Merrow (from Irish ', Middle Irish ' or ') is a mermaid or merman in Irish folklore. The term is anglicised from the Irish word murúch.
The merrows supposedly require a magical cap (; anglicised: cohuleen druith) in order to travel between deep water and dry land.
Overview
The term appears in two tales set in Ireland published in the 19th century: "Lady of Gollerus", where a green-haired merrow weds a local Kerry man who deprives her of the "magical red cap" ('); and "The Soul Cages" where a green-bodied grotesque male merrow entertains a fisherman at his home under the sea.
These tales with commentary were first published in T. C. Croker's Fairy Legends (1828). William Butler Yeats and others writing on the subject borrowed heavily from this work. "The Soul Cages" turned out not to be a genuine folktale, but rather a piece of fiction fabricated by Thomas Keightley.
A number of other terms in Irish are used to denote a mermaid or sea-nymph, some tracing back to mythological tracts from the medieval to the post-medieval period. The Middle Irish ' is a siren-like creature encountered by legendary ancestors of the Irish (either Goidels or Milesians) according to the Book of Invasions. This, as well as ' and ' are terms for the mermaid that appear in onomastic tales of the '. A ', literally "sea-wanderer", is the term for the mermaid .
Etymology
Current scholarship regards merrow as a Hiberno-English term, derived from Irish ' (Middle Irish ' or ') meaning "sea singer" or "siren". But this was not the derivation given by 19th century writers.
According to Croker, "merrow" was a transliteration of modern Irish ' or ', which resolved into ' "sea" + ' "maid". This "Gaelic" word could also denote "sea monster", and Croker remarked that it was cognate with Cornish ', a "sea hog". Yeats added ' as an alternative original, as that word is also synonymous with mermaid.
The corresponding term in the Scots dialect is ', derived from the Irish, with no original Scottish Gaelic form suggested.
The Middle Irish ', (from ' + ' "chant, song") with its singing melodies that held sway over seamen was more characteristic of the sirens of classical mythology, and was imported into Irish literature via Homer's Odyssey.
Synonyms
The terms ', ', and ' been listed as synonymous to "mermaid" or "sea nymph". These are Old or Middle Irish words, and usage are attested in medieval tracts. Other modern Irish terms for mermaid are given in O'Reilly's dictionary (1864); one of them, ' ("sea-maiden"), being the common term for "mermaid" in Irish today (cf. de Bhaldraithe's dictionary, 1959).
The term ', literally "sea-wanderer", has been applied, among other uses, to , a legendary figure who underwent metamorphosis into a salmon-woman.
Strictly speaking, the term ' in the ' example signifies "mermaid's melody". However, O'Clery's Glossary explains that this was rhetorically the "name of the nymphs that are in the sea". The term ' for "mermaid" also finds instance in the '. Croker also vaguely noted that ' has been used by "romantic historians" in reference to the "sea-nymphs" enountered by Milesian ships.
Folk tales
Thomas Crofton Croker's Second Volume to the Fairy Legends (1828) laid the groundwork for the folkloric treatment of the merrow. It was immediately translated into German by the Brothers Grimm. Croker's material on the merrow was to a large measure rehashed by such authors on the fairy-kind as Thomas Keightley, John O'Hanlon, and the poet William Butler Yeats.