plan vs schema

plan and schema both are nouns.

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

As nouns, schema is a hyponym of plan; that is, schema is a word with a more specific, narrower meaning than plan:

plan (noun)	schema (noun)
scale drawing of a structure	a schematic or preliminary plan
a series of steps to be carried out or goals to be accomplished	an internal representation of the world; an organization of concepts and actions that can be revised by new information about the world
an arrangement scheme

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