crate vs packing box

crate and packing box both are nouns.

Word	Noun	Adjective	Verb	Adverb
crate	Yes	No	Yes	No
packing box	Yes	No	No	No

As nouns, packing box is a hyponym of crate; that is, packing box is a word with a more specific, narrower meaning than crate:

crate: a rugged box (usually made of wood); used for shipping
packing box: a large crate in which goods are packed for shipment or storage

Other hyponyms of crate include packing case, soapbox.

crate (noun)	packing box (noun)
a rugged box (usually made of wood); used for shipping	a small chamber in which packing is compressed around a reciprocating shaft or piston to form a seal
the quantity contained in a crate	a large crate in which goods are packed for shipment or storage

crate (verb)	packing box (verb)
put into a crate; as for protection