Bitters
As their name suggests, bitters are a bitter additive made from hundreds of herbs, spices and plants used to flavor cocktails. The come in four basic tastes: sweet, sour, bitter, salty. (Yes, sweet bitters. Go figure.) Use them in moderation, too many can ruin a cocktail.
Dirty
A Dirty Martini will have olive juice added to the cocktail, slightly clouding it.
Dry
A Dry Martini will have a small amount of Vermouth. When more Vermouth is added, the martini becomes “wetter.”
Jigger
Composed of two metal cups (back to back), one cup larger than the other. The larger cup normally holds 1.5 ounces, and the smaller one, 1 ounce. Used to measure liquids.
Layering
A cool technique that gives cocktails a layered look. Some liquors are heavier or denser than others, which causes a natural separation where one will sink below or float on top of another.
Let Stand
This is when you pour your ingredients into an ice-filled shaker and don’t shake it. You are just “letting it stand” for a minute or so, then straining it into a martini glass.
Muddling
A wand-like instrument, similar to a mortar in chemistry, about 6-8 inches long, made of wood or glass that is used to mash up non-liquid cocktail ingredients that will be mixed with the liquid. It’s usually done in a mixing glass, pint glass, or shaker.
Olive Pick
A fancy toothpick used to hold olives.
On the Rocks
This is a drink with ice in it.
Part
A part refers to the relative amount of an ingredient, NOT a fixed amount. For example, if a recipe calls for 1 part X and 2 parts Y, then the final drink should have twice as much as X as it does Y. This way you can make the drink as big or little as you want.
Rimming
Some cocktails call for sugar or some other ingredient on the rim of the martini glass. This is done by wetting the rim first, with water or flavored juice, then dipping the rim in sugar and coating it.
Rinse
Some recipes call for a glass to be “rinsed” with a particular liqueur, like Vermouth. This simply means that you need to place a small amount of the liqueur in the glass and swirl it around so that the inside of the glass is evenly coated. Pour out any extra liqueur after rinsing.
Roll
Take the contents of the glass the drink has been mixed in, pour into the shaker and then pour it directly back into the same glass.Scoring
A score is a very long twist of lime, lemon or orange, ideally 2-3 inches long. This is a beautiful garnish for any cocktail. Simply dangle it over the lip of the glass.
Shake
When you take a cocktail shaker filled with ingredients and ice, and physically shake it to mix and cool your ingredients, this is shaking.
Shaker
A martini shaker is a stainless steel or glass container filled with alcohol and ice. It is used for mixing the drink.
Stir
The other method of mixing your drinks. Add your ingredients into an ice filled pitcher and stir, mixing and chilling your ingredients. If you need to use a cocktail shaker, rock gently back and forth.
Straight Up
A Straight Up, or just Up, drink has no ice. This is the opposite of “On the Rocks.”
Strainer
A device that fits onto the top of a tumbler which allows you to pour the liquid into a glass, while keeping the ice in the shaker.
Twist
A garnish made from the rind of a lemon, lime or orange.
[source]