zig-zag fold vs concertina fold

zig-zag fold and concertina fold both are nouns.

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

As nouns, zig-zag fold and concertina fold are synonyms defined as:

zig-zag fold and concertina 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 synonyms of zig-zag fold include accordion fold, z-fold.

zig-zag fold (noun)	concertina fold (noun)
a continuous parallel folding in an accordion-like fashion, that is with folds alternatively made to the front and back in zig-zag folds.	a continuous parallel folding in an accordion-like fashion, that is with folds alternatively made to the front and back in zig-zag folds.