A more thorough explanation:

keyage

Keyage is another word for quayage, which is the fee charged for the use of a wharf or dock for loading and unloading cargo from a ship.

• The shipping company had to pay a keyage fee to use the dock for unloading their cargo.
• The port authority increased the keyage rates to cover the cost of maintenance for the wharf.

These examples show that keyage is a fee charged for using a dock or wharf for loading and unloading cargo. The first example illustrates how a shipping company had to pay this fee to use the dock, while the second example shows how the fee can be increased to cover maintenance costs.