helmet: a type of hard hat that protects the head, worn, for example, by a police officer, a soldier or a person riding a bike or motorbike or playing some sports
Police in riot helmets lined the streets.
A protective helmet should be worn at all times.
Cycle helmets dramatically reduce the risk and severity of head injuries.
Look at the picture
What is a common word for the hat of a construction worker?
Is it a helmet? or a hard hat?
