Piece

n.

Heard in Donegal and Antrim

A colloquial term for a slice of bread, often prepared as a snack or a simple sandwich.

In use

I'm famished after work, I think I'll have a piece with a bit of butter.

Posh English

I am quite ravenous following my labors, so I shall partake of a slice of bread with some butter.

Same phrase, other counties