archangel

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

• noun A high-ranking angel.
• noun The eighth of the nine orders of angels in medieval angelology.

from The Century Dictionary.

• noun An angel of the highest order; a chief angel.
• noun A member of the lowest but one of the nine orders of angels composing the “celestial hierarchy” of Dionysius the pseudo-Areopagite, whose classification was adopted by Pope Gregory the Great, and is generally accepted by the theologians of the Roman Catholic Church.
• noun In botany: The name of several labiate plants, as Stachys sylvatica and species of Lamium.
• noun An umbelliferous plant, Archangelica officinalis. See angelica.
• noun A slim-bodied, thin-faced variety of domestic pigeon, of rather small size, with long head and beak, a peaked crest, and rich metallic lustrous plumage, black on the shoulders and tail, but coppery elsewhere.

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

• noun A chief angel; one high in the celestial hierarchy.
• noun (Bot.) A term applied to several different species of plants (Angelica archangelica, Lamium album, etc.).

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

• noun A powerful angel that leads many other angels, but is still loyal to a deity. (Judeo-Christian examples: Gabriel, Michael, Raphael, Uriel).
• noun In Christian angelology, an archangel is an angel from the third level or choir of angels, ranked above virtues and below powers.

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

• noun a biennial cultivated herb; its stems are candied and eaten and its roots are used medicinally
• noun an angel ranked above the highest rank in the celestial hierarchy