Optional and Open-air

Optional adjective - Subject to one's freedom of choice.

Open-air and optional are semantically related. In some cases you can use "Open-air" instead an adjective "Optional".

Nearby Words: option, optionally

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

Optional and open-air are semantically related. Sometimes you can use "Optional" instead an adjective phrase "Open-air".