optionaladjectiveuk /ˈɒp.ʃən.əl/ us /ˈɑːp-/
- Seat-belts are included as standard but electric windows are an optional extra.
- My phone came with 20 optional ringtones.
- Do come to the party - fancy dress is optional.
- There are several optional tours, for which there will be a small charge.
- The basic model is quite cheap, but there are a lot of optional extras.