zest

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Flavor or piquancy.
• noun Interest or excitement.
• noun The outermost part of the rind of an orange, lemon, or other citrus fruit, used as flavoring.
• noun Spirited enjoyment; gusto.
• transitive verb To remove small pieces from (a rind from a citrus fruit) for use as a flavoring in cooking.

from The Century Dictionary.

• To add a zest or relish to; make piquant, literally or figuratively.
• To cut, as the peel of an orange or a lemon from top to bottom into thin slips, or to squeeze, as orange-peel, over the surface of anything.
• noun The dry woody membrane covering or forming the partitions of a walnut or other nut or fruit, as an orange or a lemon.
• noun A piece of the outer rind of an orange or lemon used as a flavoring or for preserving; also, oil squeezed from such a rind to flavor liquor, etc.
• noun Relish imparted or afforded by anything; piquant nature or quality; agreeableness; charm; piquancy.
• noun Keen relish or enjoyment of anything; stimulated taste or interest; hearty satisfaction; gusto.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To cut into thin slips, as the peel of an orange, lemon, etc.; to squeeze, as peel, over the surface of anything.
• transitive verb To give a relish or flavor to; to heighten the taste or relish of.
• noun A piece of orange or lemon peel, or the aromatic oil which may be squeezed from such peel, used to give flavor to liquor, etc.
• noun Hence, something that gives or enhances a pleasant taste, or the taste itself; an appetizer; also, keen enjoyment; relish; gusto.
• noun obsolete The woody, thick skin inclosing the kernel of a walnut.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Enthusiasm.
• noun The outer skin of a citrus fruit, used as a flavouring or garnish.
• verb cooking To scrape the zest from a fruit
• verb To make more zesty

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb add herbs or spices to
• noun vigorous and enthusiastic enjoyment
• noun a tart spicy quality