The five limbs of the Hindu calendar day — tithi, nakshatra, yoga, karana and vara — resolved against local sunrise. Because every limb is fixed by the Moon and Sun rather than the clock, the panchang genuinely differs from city to city; pick yours below.
Panchang means five limbs: tithi (the lunar day, from the Moon's angular distance to the Sun), vara (the weekday and its ruling graha), nakshatra (the Moon's current lunar mansion), yoga (a combined Sun-Moon calculation) and karana (half a tithi). Between them they describe the quality of a given day, and they are what any muhurat is actually chosen from.
Sunrise sets the boundaries. A Vedic day runs sunrise to sunrise rather than midnight to midnight, so the tithi in force, the weekday's start, and the day's inauspicious stretches — Rahu Kaal, Yamaganda, Gulika — all shift with your latitude and longitude. A panchang computed for Delhi is simply the wrong panchang in Chennai, which is why this one asks for a location instead of publishing one national table.
Usually location, sometimes convention. Sunrise differs by city, and traditions differ on which day to assign a tithi that spans two sunrises. Both can be internally consistent.
A roughly ninety-minute window each day, falling at a different time depending on the weekday, traditionally avoided for starting anything important. It is computed here from your local sunrise and sunset.