philharmonic pitch vs international pitch

philharmonic pitch and international pitch both are nouns.

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

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

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

Other synonyms of philharmonic pitch include concert pitch.

philharmonic pitch (noun)	international 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