alhamdulilah vs salutation

alhamdulilah and salutation both are nouns.

Word	Noun	Adjective	Verb	Adverb
alhamdulilah	Yes	No	No	No
salutation	Yes	No	No	No

As nouns, salutation is a hypernym of alhamdulilah; that is, salutation is a word with a broader meaning than alhamdulilah:

alhamdulilah: An expression meaning 'praise God' in Arabic
salutation: (usually plural) an acknowledgment or expression of good will (especially on meeting)

Other hypernyms of alhamdulilah include greeting.

alhamdulilah (noun)	salutation (noun)
An expression meaning 'praise God' in Arabic	(usually plural) an acknowledgment or expression of good will (especially on meeting)
	an act of honor or courteous recognition
	word of greeting used to begin a letter