Open-air and Topside

Open-air adjective - Of, relating to, or held in the open air.

Topside and open-air are semantically related. In some cases you can use "Topside" instead a noun phrase "Open-air".

Topside noun - (usually plural) weather deck; the part of a ship's hull that is above the waterline.

Open-air and topside are semantically related. Sometimes you can use "Open-air" instead a noun "Topside".