Siostrach

Siostrach is a term encountered in Irish-language sources that refers to a sister in certain dialects and in archaic or literary registers. It is not the standard modern Irish word for sister, which is deirfiúr. The form siostrach appears in older manuscripts and in dialect writing, and is sometimes described as poetic or archaic. Its precise etymology is uncertain; it is generally treated as part of the kinship vocabulary of Gaelic varieties rather than as a modern everyday term. In contemporary Irish, speakers typically use deirfiúr, while siostrach may be found in historical texts, folklore, and some regional speech as a mark of traditional flavor. The word is also referenced in comparative discussions of Gaelic kinship terms, illustrating how regional varieties diverge from the standardized lexicon. See also Deirfiúr, Gaelic kinship terms.