A sandwich, usually with a hot savoury filling in a breadcake. The most common are chips, bacon, sausage and egg.
Let's have a bacon butty!
Friend.
A miner who works under contract, receiving a fixed amount per ton of coal or ore.
A workmate.
(among boys) A drudge; a cat's paw; someone who does the hard work; someone who is being taken advantage of by someone else.
Ah didn't play butty, ah promise yer. Yo all on yer mek the poor lad yer butty.
One of a pair of shoes or gloves.
I've fund one shoe, but canna see the butty no-weer.