Wiktionary
n. 1 (context nautical English) The taking onboard of bunker fuel 2 (context chiefly Nigeria English) The illicit removal of oil from a pipeline or other distribution system vb. (present participle of bunker English)
Wikipedia
Bunkering is the supply of fuel for use by ships in a seaport.
The term originated in the days of steamships, when the fuel, coal, was stored in bunkers. Nowadays the term bunker is generally applied to the storage of petroleum products in tanks, and the practice and business of refueling ships. Bunkering operations are located at seaports, and they include the storage of "bunker" (ship) fuels and the provision of the fuel to vessels. Bunkering includes the shipboard logistics of loading fuel and distributing it among available "bunkers" (on-board fuel tanks.)
Usage examples of "bunkering".
And then the anchor was hauled up and they shifted to the bunkering wharf.
We will be bunkering a full fuel load and munitions from the supply ship Aurora tomorrow, and I expect that, as soon as we spool up for our first jump, we will be going to battle stations.