despatch vs send

despatch is a noun but send is not a noun.

Word	Noun	Adjective	Verb	Adverb
despatch	Yes	No	Yes	No
send	No	No	Yes	No

As verbs, send is a hypernym of despatch; that is, send is a word with a broader meaning than despatch:

Other hypernyms of despatch include ship, transport.

despatch (noun)	send (noun)
the act of sending off something
killing a person or animal
the property of being prompt and efficient
an official report (usually sent in haste)

despatch (verb)	send (verb)
send away towards a designated goal	cause to be directed or transmitted to another place
	transfer
	broadcast over the airwaves, as in radio or television
	assign to a station
	to cause or order to be taken, directed, or transmitted to another place
	transport commercially
	cause to go somewhere
	cause to be admitted; of persons to an institution