Webster's Revised Unabridged Dictionary · 1913

Synclinal

Synclinal , adjective

[Greek {not transcribed} to incline together; sy`n with + {not transcribed} to incline.]

1.
Inclined downward from opposite directions, so as to meet in a common point or line.
2.
(Geology) Formed by strata dipping toward a common line or plane; as, a synclinal trough or valley; a synclinal fold; -- opposed to anticlinal.

A downward flexure in the case of folded rocks makes a synclinal axis, and the alternating upward flexure an anticlinal axis.

Synclinal , noun

(Geology) A synclinal fold.