Glass-Covered Room for Letting in Sunlight
Puzzle 18 of Tour the Body Pack
Question is: Glass-Covered Room for Letting in Sunlight
and the answer is: SOLARIUM
Word Meaning:
SOLARIUM — (chiefly US and Canada) A room, rooftop, balcony, or terrace, used for its abundant sunlight, especially when used as a medical treatment.
Definitions from Wiktionary.