A Nakshatra is one of 27 lunar mansions the Moon's path through the sky is divided into in Vedic astrology, each about 13°20' wide -- your birth Nakshatra is whichever one the Moon was passing through at the moment you were born.
Vedic astrology divides the 360° zodiac into 27 equal segments called Nakshatras (Sanskrit for "that which does not decay," often translated as "lunar mansion" or "constellation"), each spanning 13°20'. Because the Moon takes about 27.3 days to complete one orbit relative to the fixed stars, it moves through roughly one Nakshatra per day -- which is why your Nakshatra is tied to your Moon's exact position at birth, not your Sun sign.
Each Nakshatra is further divided into 4 padas (quarters) of 3°20' each, and each pada is associated with one syllable traditionally used for naming a child -- one of the few places Vedic astrology still shows up in everyday naming conventions across India. Your pada matters for precision: two people with the same Nakshatra but different padas can have meaningfully different chart emphasis.
Nakshatras matter beyond just a label -- they're the anchor point for the Vimshottari Dasha system (see below), they carry their own ruling planet and mythological/behavioral associations used in personality readings, and they're the primary factor checked in traditional Kundli (birth chart) matching for marriage compatibility.
Because a Nakshatra spans just over 13°, an imprecise birth time can shift which Nakshatra -- or at least which pada -- the Moon was actually in, which is why AstroKarmas flags results as approximate when you don't know your exact birth time.
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