Meaning of “supply” - Learner’s Dictionary

supply

noun us uk /səˈplaɪ/
He seems to think that I have an endless supply of money.Switch off the machine before disconnecting it from the power supply.The new dam will improve the water supply and thereby reduce hunger and disease.It was a remote mountain village with no electricity supply.They poisoned the city's water supply.
AMOUNT [ C ]

B2 an amount of something that is ready to be used:

a supply of water
food supplies
in short supply

If something is in short supply, there is little of it available.

SYSTEM [ C ]

the system of supplying something to people:

Someone has turned off the electricity supply.

(Definition of “supply noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)