flatwise

[ flat-wahyz ]
/ ˈflætˌwaɪz /

adverb

with the flat side, rather than the edge, foremost or in contact.
Also flat·ways [flat-weyz] /ˈflætˌweɪz/.

Origin of flatwise

First recorded in 1595–1605; flat1 + -wise

British Dictionary definitions for flatways

flatways

US flatwise

/ (ˈflætˌweɪz) /

adverb

with the flat or broad side down or in contact with another surface