stamp collecting vs philately

stamp collecting and philately both are nouns.

Word	Noun	Adjective	Verb	Adverb
stamp collecting	Yes	No	No	No
philately	Yes	No	No	No

As nouns, stamp collecting and philately are synonyms defined as:

stamp collecting and philately: the collection and study of postage stamps

Other synonyms of stamp collecting include stamp collection.

stamp collecting (noun)	philately (noun)
the collection and study of postage stamps	the collection and study of postage stamps