curtail vs ration

curtail is not a noun while ration is a noun.

Word	Noun	Adjective	Verb	Adverb
curtail	No	No	Yes	No
ration	Yes	No	Yes	No

As verbs, ration is a hyponym of curtail; that is, ration is a word with a more specific, narrower meaning than curtail:

curtail: place restrictions on
ration: restrict the consumption of a relatively scarce commodity, as during war

Other hyponyms of curtail include abridge, immobilise, immobilize, control, restrict.

curtail (noun)	ration (noun)
	the food allowance for one day (especially for service personnel)
	a fixed portion that is allotted (especially in times of scarcity)

curtail (verb)	ration (verb)
place restrictions on	distribute in rations, as in the army
terminate or abbreviate before its intended or proper end or its full extent	restrict the consumption of a relatively scarce commodity, as during war