Section I
What the rising sign is
The eastern horizon
The Ascendant is the degree of the ecliptic crossing the eastern horizon at the moment of birth. The whole zodiac passes over that horizon once a day, so each sign rises for about two hours, and a birth time off by a quarter of an hour can change the answer.
Rising signs are often read as the way someone meets a new situation: the first impression, as opposed to the Sun sign's sense of purpose or the Moon sign's emotional needs.