Divālī (दिवाली) is "A Hindū festival celebrated on the day of the new moon of Kārttik in honour of Kārttikeya, the god of war" according to Platts.
The word is from Prakrit diva-āliā, meaning "row of lamps". It's related to Sanskrit दीप् dīp "to glow" and आवली āvalī "row". दीप् dīp is from Proto-Indo-European *dyeu- "to shine" with derivatives meaning "sky, heaven, god". This root also became Sanskrit देव deva "heavenly, divine" as in Devanāgarī.
In Greek, *dyeu- became Ζεύς Zeus, the *d being preserved in the genitive form Διϝός or Διός.
In Latin, *dyeu- became deus "god" and dīvīnus "divine". Jupiter was formed from a combination of Iovis and pater "father". Iovis, earlier Diovis, is from *dyeu-. Compare Greek Ζευς πατηρ Zeus patēr and Sanskrit द्यौष्पितृ dyauṣ-pitṛ "sky father".
In other news, I feel compelled to share my recent photos of Berlin graffiti.