What is sun sign ?

Western astrology employs the tropical zodiac which divides the ecliptic into twelve signs of equal length starting at the first point of Aries, which is defined as the point at which the ecliptic (the apparent path of the Sun through the heavens) crosses the celestial equator at the spring equinox. It is important to note that these signs are completely independent of the astronomical constellations after which they were originally named and no longer bear any relationship to them