Solarium/səˈleriəm/ Definition 1 of 3Pro Tip 1/3Leisure Spaces Used to describe areas designed for relaxation and enjoyment in daylight. Their solarium is the perfect spot for a lazy Sunday brunch. Pro Tip 2/3Brightness Key Characterizes a room filled with natural light; great for reading or art activities. She set up her easel in the solarium for the best lighting. Pro Tip 3/3Plant Growth A solarium can serve as an indoor garden space due to ample sunlight. The solarium's tomatoes were thriving in the controlled climate.