In Adam Roberts' novel Yellow Blue Tibia, he tells us that Chernobyl means "wormwood". Apparently Ukrainian Чорнобиль Čornobyl' is a combination of Ukrainian чoрний čornyj "black" and билля byllja "grass blades". Ukrainian čornyj is undoubtedly related to Russian черный černyj "black", which seems to be from Proto-Indo-European *kers-no- from *kers- "black". In Sanskrit *kers-no- became कृष्ण kr̥ṣṇa "black". This is where we get the name of the deity Krishna, who was so called perhaps because of his association with storm clouds, or perhaps because of his dark skin.
Yellow Blue Tibia is a very enjoyable read, like Jose Chung's from Outer Space if it was set in the USSR. The title is a cross-linguistic pun. See if you can figure it out.