"This is my seventh skirt."
Translation:Bu benim yedinci eteğim.
I think I had answered you before, but to the best of my knowledge "eteklik" is something having to do with a skirt. It isn't a skirt itself. I have never heard that word over y 13 months in Turkey :)
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.
According to TDK(Turkish Language Institute) Eteklik and etek are same words. However, you can use one instead of another. After all eteklik doesn't prefer to use much in Turkey.