Stacks
Part of speech: verb
Definition: To arrange in a stack, or to add to an existing stack.
Part of speech: noun
Definition: (heading) A pile.
Piles
Part of speech: noun
Definition: A mass of things heaped together; a heap.Haemorrhoids.A large amount of.
Example sentence: I confess that I am a messy, disorganized and impatient reader: if the book doesn't grab me in the first 40 pages, I abandon it. I have piles of half-read books waiting for me to get acute hepatitis or some other serious condition that would force me to rest so that I could read more.