Leo

American Heritage® Dictionary of the English Language, Fourth Edition

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

Century Dictionary and Cyclopedia

1. n. In astronomy, an ancient zodiacal constellation, the Lion, containing Regulus, a star of magnitude 1½, and two stars of the second magnitude. It is easily found, for the pointers of the Great Bear point southerly to its brightest star, distant about 45 degrees from the southernmost of them. Four stars in the body of Leo form a characteristic trapezium, and those about the neck and mane make a sickle. It is the fifth sign of the zodiac, its symbol as such being ♌, showing the lion's mane. See cut in next column.
2. n. In zoology, the technical specific name of the lion, Felis leo, sometimes taken as a generic name , when the animal is called Leo africanus.

Wiktionary

1. n. A male given name, borne by numerous saints and 13 popes.
2. n. astronomy : A constellation of the zodiac, shaped approximately like a lion and containing the bright star Regulus.
3. n. 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).
4. n. Someone with a Leo star sign

GNU Webster's 1913

1. n. (Astron.) The Lion, the fifth sign of the zodiac, marked thus [♌] in almanacs.
2. n. A northern constellation east of Cancer, containing the bright star Regulus at the end of the handle of the Sickle.

WordNet 3.0

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