It has a strict meaning and a loose market usage, and you've walked straight into the gap.
Strictly, entitlements are the government approvals that give you the legal right to build a specific project on a specific parcel. That usually includes the zoning classification, plus whatever discretionary approvals your jurisdiction requires on top of it: a conditional use permit, a subdivision or plat, a site plan or plan of development approval, and sometimes separate stormwater or access permits from a state agency. What's required and what's discretionary differs by state and by municipality, and in some places site plan review really is administrative while in others it goes to a planning commission that can attach conditions or say no.
The loose usage is what your broker is doing. In the market, people say "entitled" to mean the zoning permits the use, and they say "shovel ready" to mean almost anything. Neither phrase tells you whether a building of your size and layout has been approved.
What to ask for, in writing: copies of every approval on the parcel, the ordinance or resolution that granted the rezoning, and any conditions of approval attached to it. Rezonings frequently come with proffers or conditions (a road improvement, a buffer, a cap on square footage or trip counts) that bind you as the next owner.
Also ask whether any approval has an expiration. Site plan approvals and use permits often lapse if you don't pull a building permit or start construction within some period, and how vested rights work once you have an approval is a state law question worth putting to a land use attorney before you go under contract.
