This section is from the "A Complete Dictionary of Dry Goods" book, by George S. Cole. Also available from Amazon: A complete dictionary of dry goods and history of silk, cotton, linen, wool and other fibrous substances,: Including a full explanation of the modern processes ... together with various useful tables.
Frog. An ornamental fastening for the front of men's coats and ladies' cloaks and waists, usually made of metal or braiding, and consisting of a spindle-shaped button attached by a cord, and corresponding with a loop on the opposite side of the garment. A pair of frogs fixed on the opposite side of the coat may allow of buttoning either way. On silk plush cloaks the frogs are generally of sealskin. [See Brandenburg]