gynaecology vs gynecology

gynaecology and gynecology both are nouns.

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

As nouns, gynaecology and gynecology are synonyms defined as:

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

gynaecology (noun)	gynecology (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