fold vs z-fold

fold and z-fold both are nouns.

Word	Noun	Adjective	Verb	Adverb
fold	Yes	No	Yes	No
z-fold	Yes	No	No	No

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

fold: an angular or rounded shape made by folding
z-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 fold include plait, pleat, kink, twirl, twist, pucker, ruck, accordion fold, concertina fold, zig-zag fold.

fold (noun)	z-fold (noun)
the act of folding	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 pen for sheep
a folded part (as in skin or muscle)
a group of people who adhere to a common faith and habitually attend a given church
a group of sheep or goats
a geological process that causes a bend in a stratum of rock
an angular or rounded shape made by folding

fold (verb)	z-fold (verb)
incorporate a food ingredient into a mixture by repeatedly turning it over without stirring or beating
become folded or folded up
bend or lay so that one part covers the other
confine in a fold, like sheep
cease to operate or cause to cease operating