noun

 

water the part at the end of a pipe which controls the flow of water

the cold/hot tap

 

knock a gentle knock or touch, or the noise made by knocking something gently

I felt a tap on my shoulder.

 

telephone a small piece of equipment that can be fixed to someone's telephone in order to listen to their telephone calls

 

verb

 

knock to knock or touch something gently

She tapped her fingers nervously on the table.

 

a supply If you tap a supply of something, you use what is available.

There are immense natural resources here waiting to be tapped.

 

telephone to use a special piece of equipment to listen to someone's telephone calls

I think the phone's been tapped.