Leo

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

• noun A constellation in the Northern Hemisphere near Cancer and Virgo, containing the bright stars Regulus and Denebola.
• noun The fifth sign of the zodiac in astrology.
• noun One who is born under this sign.

from The Century Dictionary.

• noun In astronomy, an ancient zodiacal constellation, the Lion, containing Regulus, a star of magnitude 1½, and two stars of the second magnitude.
• noun In zoology, the technical specific name of the lion, Felis leo, sometimes taken as a generic name , when the animal is called Leo africanus.

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

• noun (Astron.) The Lion, the fifth sign of the zodiac, marked thus [♌] in almanacs.
• noun A northern constellation east of Cancer, containing the bright star Regulus at the end of the handle of the Sickle.
• noun a small constellation between Leo and the Great Bear.

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

• proper noun A male given name, borne by numerous saints and 13 popes.
• proper noun astronomy : A constellation of the zodiac, shaped approximately like a lion and containing the bright star Regulus.
• proper noun astrology : The zodiac sign for the Lion, ruled by the Sun and covering July 23 - August 22 (tropical astrology) or August 16 - September 15 (sidereal astrology).
• noun Someone with a Leo star sign

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

• noun a zodiacal constellation in northern hemisphere between Cancer and Virgo
• noun (astrology) a person who is born while the sun is in Leo
• noun the fifth sign of the zodiac; the sun is in this sign from about July 23 to August 22