Noun

1. A double-ended vessel, generally of stainless steel or other metal, one end of which typically measures 1 1/2 fluid ounces, the other typically 1 fluid ounce.
2. One who jigs.
3. A measure of 1 1/2 fluid ounces of liquor.
4. A device for producing flatware.
5. A device used in the dyeing of cloth.
6. A sandflea, Tunga penetrans, of the order Siphonaptera.
7. A wooden or metal headed golf club used to play low flying shots to the putting green from short distances.
8. An ingenious device used by fishermen to set their nets under the ice of frozen lakes. It consists of a plank of wood with an arm on it with a sharp metal tooth on the end of the arm. A rope is tied to the arm which, when pulled, propels the plank along the underside of the ice because the tooth catches the ice. Releasing the rope allows the tooth to sink away from the ice, and when the rope is tightened again, the tooth grabs the ice farther along, allowing the jigger to crawl along the underside of the ice.
9. An alleyway separating the backs of two rows of houses.

Quotations

1998-2002: A good jigger will have a well formed lip that will pour a clean stream into the cocktail shaker or glass. — Robert B. Hess, in Jigger in DrinkBoy.com

Hand jiggers consisted of two iron frames with a spindle in each - the driving spindle with its iron belt pulley approximately 20 inches in diameter and the driven spindle with a small wooden pulley. — Pottery Jobs: Jiggering on thepotteries.org

Verb

1. To alter or adjust, particularly in ways not originally intended.

   You'll have to jigger it from the original specifications to get it to work.

2. To use a jigger.