echocardiograph vs sonograph

echocardiograph and sonograph both are nouns.

Word	Noun	Adjective	Verb	Adverb
echocardiograph	Yes	No	No	No
sonograph	Yes	No	No	No

As nouns, sonograph is a hypernym of echocardiograph; that is, sonograph is a word with a broader meaning than echocardiograph:

echocardiograph: a sonograph that creates an image of the heart and its abnormalities
sonograph: an instrument that uses the differential transmission and reflection of ultrasonic waves in order to provide an image of a bodily organ

echocardiograph (noun)	sonograph (noun)
a sonograph that creates an image of the heart and its abnormalities	an instrument that uses the differential transmission and reflection of ultrasonic waves in order to provide an image of a bodily organ