"This is my seventh skirt."
Translation:Bu benim yedinci eteğim.
it certainly is NOT used in modern Turkish. I have never heard it in my life. It is sometimes used for the piece of cloth you intend to use to create a skirt
edit: TDK BTS (büyük Türkçe sözlük) includes almost all the words in the language, although some are archaic or local.