gynecology vs gynaecology

gynecology and gynaecology both are nouns.

Word	Noun	Adjective	Verb	Adverb
gynecology	Yes	No	No	No
gynaecology	Yes	No	No	No

As nouns, gynecology and gynaecology are synonyms defined as:

gynecology and gynaecology: the branch of medicine that deals with the diseases and hygiene of women

gynecology (noun)	gynaecology (noun)
the branch of medicine that deals with the diseases and hygiene of women	the branch of medicine that deals with the diseases and hygiene of women