"Up" or "straight up:" A drink that has been mixed with ice but is served without. The term often implies that the drink will be served in a martini-style cocktail glass.

On the rocks: Served over ice.

Neat: Undiluted by ice, water or mixers.

Bitters: A highly concentrated flavoring agent made from roots, barks, herbs, berries and fruit. Nonpotable bitters are used in extremely small quantities. Potable bitters include Campari, which can be drunk on its own as well as being used as a flavoring agent.

Muddled: When ingredients are mashed or crushed with a spoon or a "muddler" (a long wooden or metal rod) so that they will better release their flavors into the drink.

Twist: A sliver of citrus peel twisted to release the essential oils and added to drinks as a delicately flavored garnish.

-- China Millman