In the shipping industry, the word bunker is used for fuel and lube oils, which are stored on ships and used for machinery operation only. If a vessel is carrying marine fuel or lube oil to discharge it to another port, it will not be called “bunker”. If the vessel or truck is carrying it to transfer to another ship for using in its machinery, it will be termed as “bunker” and the operation performed to transport the oil is known as “bunkering”. | Marine Insight