Flatbread
A broad, technically vague term covering many genuinely different unleavened and leavened topped or plain breads worldwide (naan, lavash, pita, Flammekueche, and others), increasingly used in Western food marketing as a softer-sounding, perceived-as-lighter alternative label for what is functionally a thin-crust pizza — with no fixed technical definition distinguishing 'flatbread' from 'pizza' on menus that use both terms.
Common misuse
Marketing a thin-crust pizza as a 'flatbread' to imply it is a lighter or more premium product, despite no fixed technical distinction between the two on most menus.
Related
Evidence
Generally accepted- The Oxford Companion to Food — Oxford University Press