pro ‧ tec ‧ tor /prəˈtektə $ -ər/ BrE AmE noun [countable]
[ Word Family: noun : ↑ protection , ↑ protector , ↑ protectionism , ↑ protectionist , ↑ protectiveness , ↑ protectorate ; adjective : ↑ protected ≠ ↑ unprotected , ↑ protective , ↑ protectionist ; verb : ↑ protect ; adverb : ↑ protectively ]
someone or something that protects someone or something else