The term 'butter slice' can be broken down into three separate words: PAT (3 letters), PATS (4 letters), and SLAB (4 letters). PAT is an abbreviation for the word 'patty, ' which is a flat, round cake of ground meat or vegetables. PATS is an abbreviation for 'pats of butter, ' which are small pieces of butter that are usually used to spread on food. Finally, SLAB is an abbreviation for 'SLAB of butter, ' which is a large block of butter that is usually cut into smaller pieces. All together, the term 'butter slice' refers to a thin slice of butter, usually cut from a SLAB of butter.