I’ve (more or less) figured out my definition of bread. What is my definition of sliced?
Wiktionary defines “sliced” as something that has been cut into slices.
The definition of “slice“, then, is “A thin, broad piece cut off; as, a slice of bacon; a slice of cheese; a slice of bread.” The idea of a thin slice seems to imply something that can be sliced into numerous pieces where the thinness and broadness is such that it is always more broad than thick. And if you take off one slice, there’s more than just one slice left.
This in my mind rules out what you’d normally do to a roll, bagel, panino, and so on in terms of cutting them into two bits, as Jon implies, which doesn’t really strike me as slicing at all.
So as long as I eat bread in chunks or portions that are not slices, I’m fine.