dose vs overdose

dose is a noun but overdose is not a noun.

Word	Noun	Adjective	Verb	Adverb
dose	Yes	No	Yes	No
overdose	No	No	Yes	No

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

dose (noun)	overdose (noun)
a measured portion of medicine taken at any one time
street name for lysergic acid diethylamide
the quantity of an active agent (substance or radiation) taken in or absorbed at any one time
a communicable infection transmitted by sexual intercourse or genital contact

dose (verb)	overdose (verb)
administer a drug to	dose too heavily
treat with an agent; add (an agent) to