geosyncline
noun
geo·syn·cline ˌjē-ō-ˈsin-ˌklīn 
: a great downward flexure of the earth's crust
geosynclinal
ˌjē-ō-ˌsin-ˈklī-nəl
adjective 
Word History
First Known Use
1895, in the meaning defined above
- quadroons
- quadrophonics
- quadru-
- quadrual
- Quadrula
- quadrumana
- quadrumanal
- quadrumane
- quadrumanes
- quadrumanous
- quadrumvir
- quadrumvirate
- quadrumvirates
- quadrumvirs
- quadruped
- quadrupedal
- quadrupeds
- quadrupl
- quadruplane
- quadruple
- quadruple amputee
- quadruple counterpoint
- quadruple point
- quadruple star
- quadruple thread