Overview
A bowser is a tanker of various kinds, named for Sylvanus Bowser who is credited with inventing the automobile fuel pump.
Water
The term bowser is used by water companies in the United Kingdom to refer to mobile water tanks deployed to distribute fresh water in emergencies where the normal system of piped distribution has broken down or is insufficient.
Fuel
Bowser also describes a fuel tanker used to deliver fuel to aircraft at airports or airfields. The term also describes refuelling boats that supply seaplanes, army fuel tankers used for combat resupply, and vehicles that fill heavy construction equipment such as hydraulic excavators and bulldozers. Even aircraft have been described as "flying fuel bowsers" when configured to ferry fuel to support a forward operation.
From Wikipedia (CC BY-SA 4.0).