A chamber or place dedicated to the observation or worship of the dawn or aurora.
From Latin Aurora (goddess of dawn) plus the suffix -ium, which is used to create Latin nouns for buildings or places, similar to 'auditorium' or 'natatorium.'
While not a common word today, 'aurorium' shows how Romans had special places for everything—they might have had rooms positioned to catch the first light of dawn for meditation or religious observation.
Complete word intelligence in one call. Free tier — 50 lookups/day.