I. tank 1 S2 W2 /tæŋk/ BrE AmE noun [countable]
[ Date: 1600-1700 ; Language: Portuguese ; Origin: tanque 'pool' ]
1 . a large container for storing liquid or gas:
The water tank is leaking.
Somehow the chemical got from a storage tank into water supplies.
fish/marine/breeding tank (=for keeping or breeding fish in)
the plane’s fuel tank
petrol tank British English gas tank American English
2 . ( also tankful ) the amount of liquid or gas held in a tank:
We set off next day on a full tank.
a tankful of petrol
a heavy military vehicle that has a large gun and runs on two metal belts fitted over its wheels
4 . a large artificial pool for storing water
5 . in the tank American English informal failing and losing money
be/go in the tank
Sales can’t keep going up, but that doesn’t mean the industry is going in the tank.
⇨ ↑ think tank , ↑ septic tank , ↑ drunk tank
II. tank 2 BrE AmE verb
1 . [intransitive] to decrease quickly or be very unsuccessful:
Not long after the chairman resigned, shares in the company tanked.
2 . [intransitive] British English informal to travel very fast in a car or vehicle
3 . [intransitive] informal to fail badly and be very unsuccessful SYN flop :
His last film tanked in the States, but did well in the UK.
4 . ( also tank it ) [transitive] to deliberately lose a sports game that you could have won
tank up phrasal verb
especially American English to put petrol in your car so that the tank is full SYN fill up