Guardian or protector: a person responsible for the care or protection of someone (often used to refer to parents at school events).
保護者会は来週の金曜日に開催されます。
The parents' (guardians') meeting will be held next Friday.
学校は保護者に連絡を取って事情を説明した。
The school contacted the guardians to explain the situation.
保護者の同意がなければ参加できません。
You cannot participate without a guardian's consent.