■ noun
1》 a lamp with a transparent case protecting the flame or electric bulb.
↘the light chamber at the top of a lighthouse.
2》 a square, curved, or polygonal structure on the top of a dome or a room, with glazed or open sides.
Origin
ME: from OFr. ~e , from L. ~a , from Gk lamptēr 'lamp', from lampein 'to shine'.