From calendar rules to cultural meaning
Vrata, pūjā, and observance
Astronomy can tell us which tithi or other calendar pattern is present. A named cultural or religious observance appears only when a documented rule connects that condition with a particular practice or occasion.
Two words you will meet often
Vrata and pūjā describe forms of religious participation.
Vrata
A religious observance or disciplined undertaking, which may include fasting, prayer, or other practices.
Pūjā
Ritual worship or an offering made with devotion.
The same calendar pattern can carry different meanings in different traditions. Open Pañcāṅga therefore names the rule and context instead of assigning one universal practice to every matching tithi.