a device that shreds documents (usually in order to prevent the wrong people from reading them)
"After gathering all his sensitive financial records, he fed each page into the shredder before leaving for work."
A machine that tears up objects into smaller pieces, especially a paper shredder or garbage shredder.
"After sorting through the overflowing recycling bin, I realized we needed to buy a new shredder for all those old magazines and receipts."