How do you say nebula in Hindi?
— नीहारिका (f) (nīhārikā)

Generic synonyms for nebula in Hindi
cloudमेघ (m) (megh); बादल (m) (bādal); अभ्र (m) (abhr)
Specialized synonyms for nebula in Hindi
planetary nebulaग्रहीय नीहारिका