Pisces

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

• noun A constellation in the equatorial region of the Northern Hemisphere near Aries and Pegasus.
• noun The 12th sign of the zodiac in astrology.
• noun One who is born under this sign.

from The Century Dictionary.

• A constellation and sign of the zodiac; the Fishes.
• In zoology, a class of vertebrates, the fishes, to which different limits have been assigned. See fish.

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

• noun plural The twelfth sign of the zodiac, marked ♓ in almanacs.
• noun plural A zodiacal constellation, including the first point of Aries, which is the vernal equinoctial point; the Fish.
• noun plural (Zoöl.) The class of Vertebrata that includes the fishes. The principal divisions are Elasmobranchii, Ganoidei, and Teleostei.

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

• proper noun astronomy A constellation of the zodiac supposedly shaped like a pair of fish.
• proper noun astrology The zodiac sign for the fish, ruled by Neptune and covering February 20 - March 20 (tropical astrology) or March 15 - April 14 (sidereal astrology).
• noun Someone with a Pisces star sign

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

• noun a large faint zodiacal constellation; between Aquarius and Aries
• noun the twelfth sign of the zodiac; the sun is in this sign from about February 19 to March 20
• noun a group of vertebrates comprising both cartilaginous and bony fishes and sometimes including the jawless vertebrates; not used technically
• noun (astrology) a person who is born while the sun is in Pisces