sustain vs bracket

sustain is not a noun while bracket is a noun.

Word	Noun	Adjective	Verb	Adverb
sustain	No	No	Yes	No
bracket	Yes	No	Yes	No

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

Other hyponyms of sustain include scaffold, block, carry, chock, buoy, buoy up, pole, underpin, prop, prop up, shore, shore up, truss, brace.

sustain (noun)	bracket (noun)
	a support projecting from a wall (as to hold a shelf)
	either of two punctuation marks ([ or ]) used to enclose textual material
	either of two punctuation marks (`<' or `>') used in computer programming and sometimes used to enclose textual material
	a category falling within certain defined limits

sustain (verb)	bracket (verb)
undergo (as of injuries and illnesses)	classify or group
establish or strengthen as with new evidence or facts	place into brackets
admit as valid	support with brackets
supply with necessities and support
provide with nourishment
be the physical support of; carry the weight of
lengthen or extend in duration or space