
“Ownership” as a social construct is a claim other people recognize and agree not to violate. Deeds, titles, and bank balances only mean something because a whole system agrees they do. Your body is different. Your claim to ownership doesn't come from anyone's agreement. You're the one living in it. A state can override that claim, but it can't be the source of it. That's the difference between owning something and controlling it.
One definition, not two: ownership is a rightful claim to use and control something. The difference is where the claim comes from. Your house's claim is granted by a system and can be revoked by it. Your claim to your body isn't granted by anyone. It comes from the fact that you're the one inhabiting it. Conscription doesn't disprove that claim, it violates it. If the state were the source, the draft wouldn't be controversial.
Imagine yourself completely alone on an island. No government, no laws, not any other people. Your house, car, and money stop being yours, because there's no one left to agree they are. Your body is still yours. And being violated doesn't end ownership. A kidnapped person doesn't become the kidnapper's property. That's why it's a crime. The system can rightfully take your house. No one can rightfully take you.