The Collaborative International Dictionary
Synclinorium
Synclinorium \Syn`cli*no"ri*um\, n.; pl. Synclinoria. [NL.,
fr. Gr. ? to lay together + ? mountain.] (Geol.)
A mountain range owing its origin to the progress of a
geosynclinal, and ending in a catastrophe of displacement and
upturning.
--Dana.
Wiktionary
synclinorium
n. (context geology English) A large syncline with superimposed smaller folds.