Property

Scarce things you own, starting with your body and extending to whatever you first took into use when no one owned it, or received by voluntary transfer. Only scarcity makes something property: two agents cannot both use the same thing at once, so someone must decide, and first use or transfer says who. Creation alone confers nothing. Sharing an idea loses nothing, and a thing shaped from another's material stays theirs. Stealing property is harm; you're the sole boss of it, as per natural rights from logic.