GEOSYNCLINAL

Ge′o‐syn‐cli″nal (?), n. [[Gr. γέα, γη̑, the earth + E. synclinal.]] (Geol.) the downward bend or subsidence of the earth's crust, which allows of the gradual accumulation of sediment, and hence forms the first step in the making of a mountain range; — opposed to geanticlinal.