synclinal

adjective

syn·​cli·​nal (ˌ)sin-ˈklī-nᵊl 

1

: inclined down from opposite directions so as to meet

2

: having or relating to a folded rock structure in which the sides dip toward a common line or plane

Word History

Etymology

Greek syn- + klinein to lean — more at lean

First Known Use

1833, in the meaning defined at sense 1