flexure vs zig-zag fold

flexure and zig-zag fold both are nouns.

Word	Noun	Adjective	Verb	Adverb
flexure	Yes	No	No	No
zig-zag fold	Yes	No	No	No

As nouns, zig-zag fold is a hyponym of flexure; that is, zig-zag fold is a word with a more specific, narrower meaning than flexure:

flexure: an angular or rounded shape made by folding
zig-zag fold: a continuous parallel folding in an accordion-like fashion, that is with folds alternatively made to the front and back in zig-zag folds.

Other hyponyms of flexure include plait, pleat, kink, twirl, twist, pucker, ruck, accordion fold, concertina fold, z-fold.

flexure (noun)	zig-zag fold (noun)
act of bending a joint; especially a joint between the bones of a limb so that the angle between them is decreased	a continuous parallel folding in an accordion-like fashion, that is with folds alternatively made to the front and back in zig-zag folds.
an angular or rounded shape made by folding
the state of being flexed (as of a joint)