Usually a flat, round piece of beef often referred to as a 'burger' or 'patty'. The production of this involves using the bicep meat of well-trained cows capable of many impressive arm curls. This is then 'compressed' using a machine featuring an array of logs which pummel the meat into a circular representation of submission.
Compressed beef is often flame-grilled in secret, and traditionally served by Meat Representatives of a non-English origin.
The first ever use of compressed beef in this fashion was pioneered by Terry Nutkins in 1944 in an attempt to pacify the Nazi threat of the time.
'What you having for lunch?'
(Hamburger, Cheeseburger, Hamburglar, Quarter Pounder, XL Bacon Double Cheeseburger, The Great Suprendo, Whopper, Big Mac)