superload vs burden

superload and burden both are nouns.

Word	Noun	Adjective	Verb	Adverb
superload	Yes	No	No	No
burden	Yes	No	Yes	No

As nouns, burden is a hypernym of superload; that is, burden is a word with a broader meaning than superload:

superload: a variable load on a structure (e.g. a bridge) such as moving traffic
burden: weight to be borne or conveyed

Other hypernyms of superload include load, loading.

superload (noun)	burden (noun)
a variable load on a structure (e.g. a bridge) such as moving traffic	weight to be borne or conveyed
	the central idea that is expanded in a document or discourse
	an onerous or difficult concern
	the central meaning or theme of a speech or literary work

superload (verb)	burden (verb)
	impose a task upon, assign a responsibility to
	weight down with a load