pension plan vs plan

pension plan and plan both are nouns.

Word	Noun	Adjective	Verb	Adverb
pension plan	Yes	No	No	No
plan	Yes	No	Yes	No

As nouns, plan is a hypernym of pension plan; that is, plan is a word with a broader meaning than pension plan:

Other hypernyms of pension plan include program, programme.

pension plan (noun)	plan (noun)
a plan for setting aside money to be spent after retirement	scale drawing of a structure
	a series of steps to be carried out or goals to be accomplished
	an arrangement scheme

pension plan (verb)	plan (verb)
	make plans for something
	have the will and intention to carry out some action
	make or work out a plan for; devise