In the Maastricht airspace we have this: (the bold part can be found in the ICAO D4444 as well)
"The term "MINIMUM FUEL" is used to describe a situation in which an aircraft's fuel supply has reached a state where little or no delay can be accepted. This fuel state still allows the aircraft to land with the prescribed minimum amount of fuel.
Should any undue delay occur, Controllers must be aware the pilot might declare an emergency situation requiring priority handling to its intended destination? OAT traffic uses in this situation normally the term "BINGO FUEL".
"The term "LOW ON FUEL" is used to indicate that the fuel supply is exhausted to such extent that it has become unlikely that the aircraft can land with the prescribed minimum amount of fuel. Controllers shall verify if the pilot is declaring an emergency situation and act accordingly."