Similar structures:
* Beacon: This is a general term for any signal that warns or guides.
* Seamark: This refers to any landmark that helps sailors navigate, including buoys and lighthouses.
* Tower: This emphasizes the tall, cylindrical structure of a lighthouse.
* Pharos: This refers specifically to a lighthouse, often in a historical or literary context.
More metaphorical:
* Guide: This emphasizes the lighthouse's role in directing ships.
* Hope: This refers to the metaphorical sense of a lighthouse as a symbol of safety and guidance.
* Sentinel: This emphasizes the lighthouse's watchful and protective role.
The best alternative will depend on the specific situation and the nuance you want to convey.