At its beginning, the word "skirt" didn't refer to a female garment at all. The modern English word "skirt" comes from the Old Norse word skyrta, meaning a shirt, a man's garment. During the Renaissance, "skirts" referred to the bottom part of a man's tunic or doublet — the skirts or tabs around the waist of the garment. Until the 19th century, the proper term for what we call a woman's skirt was "petticoat".
McGann also provides pattern suggestions, sewing tips and references for skirts.