home defence
/ˌhəʊm dɪˈfɛns/(US home defense)
noun
1Organized defence of a country's home territory against attack or invasion. Also (frequently with capital initials): an armed force or division of the armed forces responsible for this.
2Originally and chiefly US. Defence of a person's home or household against intrusion, especially by means of firearms.
Origin
Early 17th century; earliest use found in Experimentall Discoverie Spanish Practises. From home + defence.