I. -shən ə l, -shnəl adjective
: involving or depending on the exercise of an option : left to the discretion of the one concerned : not compulsory or obligate
an optional activity
formal dress is optional
• op·tion·al·i·ty ˌäpshəˈnaləd.ē noun -es
• op·tion·al·ly ˈäpshən ə lē, -shnəlē, -li adverb
II. noun
( -s )
1. : something that is optional
2. chiefly Britain : elective