“Rashi” means arrangement of stars. As per astrology rashis are named as per their arrangement, which resembles particular animal. For e.g., Vrishchika (Scorpio) rashi have the arrangement of stars that resembles scorpion. There are 12 rashis according to Hindu astrology.
I think rashi represents the Zodiac signs. Based on ones Rashi, they can consider the exact time of the birth. There are about 12 rashi's in Hindu. The rashi's according to the hindu system are mesha, vrishabha, mithuna, kataka, simha, kanya, tula, vrischika, dhanu, makara etc.
These signs helps in representing the collection of stars in a particular alignment.
In Hindi the signs of the zodiac are called “rashis”. There are 12 Birth Rashis like Mesha (Aries), Vrishabha (Taurus), Mithun (Gemini), Karka (Cancer), Simha / Sinh (Leo), Kanya (Vigro), Tula (Libra), Vruschika (Scorpius), Dhanu (Sagittarius), Makar (Capricorn), Kumbha (Aquarius), and Meena (Pisces). The period of the rashi starts about after 3 weeks from the start of the corresponding zodiac sign.