The term 'tankerful' is a combination of the words 'TANKER' and 'FULL'. It is used to describe a large TANKER ship that is filled with OIL. The crossword solutions for this term are OIL, which is a three-letter word. OIL is a fossil fuel that is used to power many things, from cars to factories. Tankers are ships that are used to transport OIL from one place to another. A tankerful of OIL is a TANKER that is filled to capacity with OIL.