curettage vs surgical operation

curettage and surgical operation both are nouns.

Word	Noun	Adjective	Verb	Adverb
curettage	Yes	No	No	No
surgical operation	Yes	No	No	No

As nouns, surgical operation is a hypernym of curettage; that is, surgical operation is a word with a broader meaning than curettage:

curettage: surgery to remove tissue or growths from a bodily cavity (as the uterus) by scraping with a curette
surgical operation: a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body

Other hypernyms of curettage include operation, surgery, surgical procedure, surgical process.

curettage (noun)	surgical operation (noun)
surgery to remove tissue or growths from a bodily cavity (as the uterus) by scraping with a curette	a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body