The zodiac is divided two ways in Indian astrology. The twelve rashis of 30 degrees each are the familiar division. The 27 nakshatras of 13 degrees 20 minutes each are the older one, and for most practical purposes the more informative. Your nakshatra is the one the Moon occupied at your birth.
Why it needs a birth time
The Moon crosses one nakshatra in roughly a day, so the date alone narrows it to one or two possibilities but cannot settle it. A birth near a boundary can fall either side depending on a few minutes. This is why a nakshatra given without a birth time should be treated as provisional.
Padas: the quarter you were born in
Each nakshatra is divided into four padas of 3 degrees 20 minutes. The pada decides the syllable traditionally used for naming, and it places the Moon in a specific sign of the navamsha chart, which matters for marriage analysis. Two people in the same nakshatra but different padas can read quite differently.
Gana, yoni and nadi
Every nakshatra carries three attributes used directly in marriage matching. Gana classifies temperament as deva, manushya or rakshasa. Yoni assigns an animal, used to read physical compatibility. Nadi assigns one of three constitutional types — adi, madhya or antya — and a shared nadi between two charts is the single heaviest objection in Ashtakoota Milan, worth eight of the 36 points.
What your nakshatra describes
The Moon's nakshatra is the strongest single indicator of temperament in a chart — closer to what people mean by personality than the Sun sign is. It carries a ruling planet, which starts your Vimshottari dasha sequence, a deity, and a symbol that usually says more about the nakshatra than any adjective.
Ashwini's symbol is a horse's head and its deity is the twin physicians of the gods. Speed and healing run through everything it touches.