H3, H03 or H-3 may refer to: Entertainment Happy Hustle High, a manga series by Rie Takada, originally titled "H3 School!" H3 (film), a 2001 film about the 1981 Irish hunger strike h3h3Productions, styled "[h3]", a satirical YouTube channel Science Triatomic hydrogen (H3), an unstable molecule Trihydrogen cation (H3+), one of the most abundant ions in the universe Tritium (Hydrogen-3, or H-3), an isotope of hydrogen ATC code H03 Thyroid therapy, a subgroup of the Anatomical Therapeutic Chemical Classification System British NVC community H3, a heath community of the British National Vegetation Classification system Histamine H3 receptor, a human gene Histone H3, a component of DNA higher structure in eukaryotic cells , one of the three laryngeals in the reconstructed Proto-Indo-European language Hekla 3 eruption, a huge volcanic eruption around 1000 BC Computing , the level-3 HTML heading markup element HTTP/3, the third revision of a protocol for the World Wide Web Socket H3, the common name of the LGA 1150 CPU socket Transportation Air and space H3 (rocket), an expendable launch system under development by Japan Aerospace Exploration Agency Harbour Air Seaplanes (IATA code), a Canadian charter airline H-3 Air Base, former Iraqi Air Force base in western Iraq H-3 Sea King, a United States Navy helicopter Standard H-3, an improved version of the 1916 Standard H-2 aircraft Automobiles Brilliance H3, a Chinese compact sedan Haval H3, a Chinese compact SUV Huansu H3, a Chinese compact MPV Hummer H3, an American mid-size SUV Ships USS H-3 (SS-30), a 1914 United States Navy H-class submarine HMS Grenville (H03), a 1935 British Royal Navy destroyer HMS H3, a 1915 British Royal Navy H-class submarine Rail H3 series of METRORail tramways in Houston GNR Class H3, a class of British steam locomotives Roads H3 Monks Way, a road part of the Milton Keynes grid road system, United Kingdom Interstate H-3, a highway in Hawaii Other uses H3 (classification), a para-cycling classification H3, an 18th-century marine chronometer by John Harrison H3, a type of automotive halogen lamp H3 (pyrotechnics), a pyrotechnic composition H3 Hardy Collaboration Architecture, a firm started by Hugh Hardy H3 Pharmaceutical Chemistry, an advanced subject for GCE A-level students in Singapore DSC-H3, a 2008 Sony Cyber-shot camera Hash House Harriers, an international group of non-competitive running, social and drinking clubs H3 (Kuwait), an archaeological site See also 3H (disambiguation) HHH (disambiguation) Triple H (disambiguation)