optional

/ˈɑpʃənəl/
adjective
  1. Available to be chosen but not required; not mandatory.
    • The salad dressing is optional; you can have the salad plain.
    • The company offers optional health insurance for part-time workers.
    • The field trip is optional, so you can decide if you want to go.
What does "optional" mean? | whatsthatwordmean | whatsthatwordmean