possibility out of several that can be chosen; choice

Alternative form of clothing optional

Alternative form of nonoptional.

(naturism) Allowing and encouraging nudity but tolerating the wearing of clothes, as between nudist and clothing compulsive. Abbreviation: C.O.

(US, military, aviation) An aircraft that may be manned or unmanned, able to function in either mode without modification.

plural of optionally piloted vehicle

plural of European option

plural of American option

plural of Bermudan option

(finance) An option that can be exercised at specific dates between issue date and expiry date. Sometimes known as a mid-Atlantic option.