Territorial means defending its own space against others. A territorial cat, territorial behaviour, very territorial.
In animals it describes defending a patch for food or breeding, marked by scent, song or display, and most fights are avoided by the marking rather than caused by it. Of people it means possessive about your own area of work or home. In politics, territorial waters extend twelve nautical miles from the coast, and a territorial dispute is an argument over borders. Note the Territorial Army, Britain's reserve force.
1adjectiveterritorialDefending its own space against others.
“Our cat is very territorial and hisses at any other cat that comes into the garden.”
2adjectiveareaTo do with an area of land or its borders.
“Territorial waters run about twelve miles out.”
territorial is a quality of defending space.
Latin territorium is the land round a town, probably from terra, earth. Terrain, terrace and terrier — a dog that goes to earth — come from the same ground.
Proto-Indo-European
*ters-
Latin
territorialis
English, today
territorial
Borrowed from Latin territorialis, from Latin territorium; equivalent to territory + al.
Etymology from Wiktionary, CC BY-SA