In astrology a Sun-sign is generally the sign of the zodiac that the Sun was in when a person was born.
Although it is often stated in newspapers and magazines that the Sun-sign is the sign of the zodiac that the Sun was in on the day of a person’s birth, technically the Sun-sign is more accurately defined as the sign of the zodiac that the Sun was in at the exact moment of birth. This is because the Sun can move from one sign to another during certain days, when the Sun is close to the cusp of one of the signs, and so in these instances the exact time of birth can make a difference.
Sun-signs are used the most widely within the context of horoscope columns which utilize Sun-sign astrology. In Sun-sign astrology only the position of the Sun at the birth of the individual is known, and the rest of the birth chart is not taken into account. Despite this, because of their focus on the moment of birth, Sun-signs fall under the branch of natal astrology.