optional UK /ˈɒp.ʃə.nəl/US /ˈɑp.ʃə.nəl/noun 2adjective 1forms 1 noun2 •Something that is not compulsory, especially part of an academic course. •In various programming languages, a kind of variable that is assigned a specific data type but may or may not hold an actual value. adjective1 •Not compulsory; left to personal choice; elective.On that beach clothing is entirely optional. formsoptionals
