op·tion·al 
/ˈɑ:pʃənl̟/ adjective
/ˈɑ:pʃənl̟/ adjective : available as a choice but not required
▪ Jackets are required at the restaurant, but ties are optional. ▪ Many optional features are available on this car. ▪ Registration is optional, not mandatory.
▪ Jackets are required at the restaurant, but ties are optional. ▪ Many optional features are available on this car. ▪ Registration is optional, not mandatory.
