get onto vs twig

get onto is not a noun while twig is a noun.

Word	Noun	Adjective	Verb	Adverb
get onto	No	No	Yes	No
twig	Yes	No	Yes	No

As verbs, get onto and twig are synonyms defined as:

Other synonyms of get onto include catch on, cotton on, get it, get wise, latch on, tumble.

get onto (noun)	twig (noun)
	a small branch or division of a branch (especially a terminal division); usually applied to branches of the current or preceding year

get onto (verb)	twig (verb)
understand, usually after some initial difficulty	branch out in a twiglike manner
	understand, usually after some initial difficulty