dam vs milldam

dam and milldam both are nouns.

Word	Noun	Adjective	Verb	Adverb
dam	Yes	No	Yes	No
milldam	Yes	No	No	No

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

dam: a barrier constructed to contain the flow of water or to keep out the sea
milldam: dam to make a millpond to provide power for a water mill

Other hyponyms of dam include weir.

dam (noun)	milldam (noun)
female parent of an animal especially domestic livestock	dam to make a millpond to provide power for a water mill
a barrier constructed to contain the flow of water or to keep out the sea
a metric unit of length equal to ten meters

dam (verb)	milldam (verb)
obstruct with, or as if with, a dam