The Collaborative International Dictionary
Syncline \Syn*cline"\, n. (Geol.) A synclinal fold.
Douglas Harper's Etymology Dictionary
1855, back-formation from synclinal.
Wiktionary
n. (context geology English) A concave-upward fold in rock strata
Wikipedia
In structural geology, a syncline is a fold with younger layers closer to the center of the structure. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed smaller folds. Synclines are typically a downward fold, termed a synformal syncline (i.e. a trough); but synclines that point upwards, or perched, can be found when strata have been overturned and folded (an antiformal syncline).
Usage examples of "syncline".
All you have to do is land us very quietly in a nice, deep syncline, and give me sufficient data on the terrain.
We divided our five minutes between conversation in deep-level thinker language, transfer of experiences, and cross-diagnostic, to see whether bad syncline searches could occur in any of our neural systems.
I made my requests and it pulled answers out of its non-trivial syncline searches.
The area in which he regained his footing was the lowest point in the syncline in which the cemetery was situated.
In an eroded cliff face, she had noticed a little syncline of a dark material that looked to be asphaltite.
The folds of rock streaming by, the swells and grabens, the benches, spires, and synclines linked and continued.