General Certificate of Secondary Education vs GCSE

General Certificate of Secondary Education and GCSE both are nouns.

Word	Noun	Adjective	Verb	Adverb
General Certificate of Secondary Education	Yes	No	No	No
GCSE	Yes	No	No	No

As nouns, General Certificate of Secondary Education and GCSE are synonyms defined as:

General Certificate of Secondary Education and GCSE: the basic level of a subject taken in school

Other synonyms of General Certificate of Secondary Education include O level.

General Certificate of Secondary Education (noun)	GCSE (noun)
the basic level of a subject taken in school	the basic level of a subject taken in school