1. (noun) a structure commanding a wide view of its surroundings

• lookout
• lookout station
• observation tower

1. (noun) a building designed and equipped to observe astronomical phenomena

• building
• edifice

2. (noun) a structure commanding a wide view of its surroundings

• construction
• structure

1. (noun) a structure commanding a wide view of its surroundings

• observation dome
• widow's walk

1. (noun) a structure commanding a wide view of its surroundings

• look out
• watch
• watch out