This French cuff is fastened with a silk knot.

A cuff is an extra layer of fabric at the lower edge of the sleeve of a garment covering the arms. In US usage the word may also refer to the end of the leg of a pair of trousers. The functional purpose of turned cuffs is to protect the material from fraying and, when frayed, to allow the cuffs to be repaired or replaced without major changes to the garment.

Cuffs may be made by turning back the material, or a separate band of material may be sewn on or worn separately attached by buttons or studs. A cuff may show an ornamental border, or have an addition of lace or other trimming.

Shirt cuffs[link]

Except on casual attire, shirt cuffs are generally divided down one edge and then fastened together, so they can let a hand through and then fit more snugly around the wrist. Some sweaters and athletic garments (both tops and pants) have cuffs that either contain elastic or are woven so as to stretch around a hand or foot and still fit snugly, accomplishing the same purpose.

Divided shirt cuffs are of three kinds, depending on how they fasten:

• Button cuffs, also called barrel cuffs, have buttonholes on the one side and buttons on the other (sometimes more than one, so that the fit can be adjusted).
• Link cuffs, which have buttonholes on both sides and are meant to be closed with cufflinks or silk knots. They are most commonly fastened in either the "kissing" style, where the insides of both sides are pressed together, or very unusually with the outer face touching the inner face, as with a button cuff (though this is unorthodox). Link cuffs come in two kinds:
  • Single cuffs, the original linked cuff, are required for white tie and are the more traditional choice for black tie. Also, some traditionalists may wear this style with lounge suits as well.
  • Double, or French, cuffs, are twice as long and worn folded back on themselves. French cuffs were once considered to be more formal than button cuffs, although they are seeing a resurgence in the business environment, particularly in Europe. Even though traditionally French cuffs could only be worn with a lounge suit or more formal clothing (and not a sports jacket), this is now not followed by most, while some even wear these cuffs without a tie or jacket. They remain the preferred choice for semi-formal, black tie events.
• Convertible cuffs may be closed with buttons or with cufflinks.

Trouser cuffs[link]

Most trouser legs are finished by hemming the bottom to prevent fraying. Trousers with turn-ups ("cuffs" in American English), after hemming, are rolled outward and sometimes pressed or stitched into place. The main reason for the cuffs is to add weight to the bottom of the leg, to help the drape of the trousers. Originally, however, it started as men rolling up their trousers to avoid getting mud splashed on them when roads were still unpaved.

Jacket cuffs[link]

The buttons and buttonholes at the end of suit jacket sleeves are generally decorative and non-functional. "Surgeon’s cuffs" can be opened at the wrist^[1], and are traditionally associated with bespoke tailoring.

References[link]