international pitch vs philharmonic pitch

international pitch and philharmonic pitch both are nouns.

Word	Noun	Adjective	Verb	Adverb
international pitch	Yes	No	No	No
philharmonic pitch	Yes	No	No	No

As nouns, international pitch and philharmonic pitch are synonyms defined as:

international pitch and philharmonic pitch: the pitch used to tune instruments for concert performances; usually assigns 440 Hz to the A above middle C

Other synonyms of international pitch include concert pitch.

international pitch (noun)	philharmonic pitch (noun)
the pitch used to tune instruments for concert performances; usually assigns 440 Hz to the A above middle C	the pitch used to tune instruments for concert performances; usually assigns 440 Hz to the A above middle C