"Full Coverage" Is a Marketing Term
No policy is called full coverage. Knowing what the phrase omits is the point.

Ask for "full coverage" and you will get a policy. Ask what it includes and you will get different answers from different people, because the phrase has no regulatory definition. It is shorthand, and it conceals the decisions that matter.
What people usually mean
In common use it means liability plus comprehensive plus collision. That is three of the coverages on a personal auto policy. There are typically eight or nine.
What it commonly leaves out
- Uninsured/underinsured motorist — often declined or set at state minimum
- Medical payments or personal injury protection — pays your own medical costs regardless of fault
- Rental reimbursement — pays for a car while yours is repaired
- Roadside assistance
- Gap coverage
- OEM parts endorsement — whether repairs use manufacturer parts
- Diminished value — the resale loss a repaired car carries
The limits hiding underneath
Worse than the omissions are the limits. "Full coverage" at state minimum liability — in some states $25,000 per person and $50,000 per accident — is full coverage in name and catastrophically thin in practice. A single serious injury exhausts it, and the balance is pursued against you personally.
Two policies can both be sold as full coverage while one carries ten times the protection of the other. The word full describes the categories, not the amounts.
The better question
Instead of asking for full coverage, ask: "What are my liability limits, what are my UM/UIM limits, and what would happen if I caused an accident with $400,000 in injuries?" The answer to the last one tells you whether the policy does its job.