binder // noun [C]
1
a hard cover for holding loose sheets of paper together:
a ring binder
2 (Law ) (AmE)
an agreement that you sign, which, together with a first payment (deposit), gives you the right to buy a property for a limited period of time:
The binder should state that your deposit will be refunded if you are unable to get a mortgage loan.
3 (Insurance ) (AmE)
a written or spoken agreement that an insurance company will provide insurance until a permanent document is provided ⇨ COVER NOTE