Anything required is mandatory or needed. If something is required, it's not optional. You better do your required reading over the summer, or else...

To require something is to demand it, like a restaurant requiring men to wear a jacket. Anything described as required is similarly demanded by some person or organization. A license is required to drive. A credit card is required to get a hotel room. A helmet is required in football. Sometimes this word is used more loosely. For example, a glass of water will be required for most people after a workout. That just means the water is needed.

Definitions of required

adj required by rule

required reading”
compulsory, mandatory
morally or legally constraining or binding

adj necessary for relief or supply

needed, needful, requisite
absolutely essential

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, can put you on the path to systematic vocabulary improvement.