PH can refer to either: 1. Finnish heavy psych meta-rockers, formerly known as Mr. Peter Hayden 2. An experimental Irish rock band of the '80s ("Last Days"). 3. A hip-hop artist formerly known as Pumpkinhead, The Underground King, based in Brooklyn, New York. 4. A heavy metal band from Hungary. 5. Párovské Hlavy - a high-society punk band from Slovakia. 6. Turntablist Paul Hillery 7. A South African rapper and producer also known as pH Raw X.