D and C vs surgical operation

D and C and surgical operation both are nouns.

Word	Noun	Adjective	Verb	Adverb
D and C	Yes	No	No	No
surgical operation	Yes	No	No	No

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

D and C: a surgical procedure usually performed under local anesthesia in which the cervix is dilated and the endometrial lining of the uterus is scraped with a curet; performed to obtain tissue samples or to stop prolonged bleeding or to remove small tumors or to remove fragments of placenta after childbirth or as a method of abortion
surgical operation: a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body

Other hypernyms of D and C include operation, surgery, surgical procedure, surgical process.

D and C (noun)	surgical operation (noun)
a surgical procedure usually performed under local anesthesia in which the cervix is dilated and the endometrial lining of the uterus is scraped with a curet; performed to obtain tissue samples or to stop prolonged bleeding or to remove small tumors or to remove fragments of placenta after childbirth or as a method of abortion	a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body