endplate vs end organ

endplate and end organ both are nouns.

Word	Noun	Adjective	Verb	Adverb
endplate	Yes	No	No	No
end organ	Yes	No	No	No

As nouns, end organ is a hypernym of endplate; that is, end organ is a word with a broader meaning than endplate:

endplate: the flattened end of a motor neuron that transmits neural impulses to a muscle
end organ: a specialized structure at the peripheral end of some motor or sensory nerve fibers

endplate (noun)	end organ (noun)
the flattened end of a motor neuron that transmits neural impulses to a muscle	a specialized structure at the peripheral end of some motor or sensory nerve fibers