Partitives

"Partitive expressions collocate strongly with particular non-count nouns: 

a loaf of bread
two slices of bread/cake/cheese/chicken breast
a bar of chocolate/soap
a bit of fun
a piece of furniture
a stroke of luck
a spell of bad weather

 Partitive expressions commonly refer to the shape, size, movement or the amount of something:There's a whole stream of people queuing outside the post office.
He gave us a torrent of abuse.


 Some partitive expressions with -ful refer to containers or spaces which commonly hold the item referred to. These include bowlful of, cupful of, fistful of, handful of, mouthful of, spoonful of:He gave me a fistful of cash. I don't know how much it was all together.
I always add a spoonful of salt to the pasta water.