http://acronyms.thefreedictionary.com/h
H High/Height
H Hour
H Hydrogen
H Acknowledgement of Receipt (Scott Catalogue prefix; philately)
H C Language Header File (file name extension)
H Enthalpy
H Federal Reserve Bank of Saint Louis, Missouri (designates original point of circulation of a dollar bill)
H Hacker
H Half
H Half Size Blue Print
H Half-Word
H Hamiltonian (physics)
H Harbor
H Hard
H Hardness
H Hardware
H Haze (weather reports)
H Hearts (playing cards)
H Hecto- (10^3, SI Prefix)
H Heer (German)
H Helicobacter (genus of H. pylori bacteria)
H Helicopter or Search/Rescue (US military aircraft designation; as in H-1)
H Hell
H Help! (Beatles song)
H Henry
H Hentai (anime)
H Hexadecimal
H High Risk
H Hijrah
H Himalayan (rabbit breed)
H Hinge (philately)
H Histamine
H Histidine (amino acid)
H Historical (action code)
H Hit (Baseball)
H Hold (baseball; relief pitcher stat)
H Holder (football)
H Hologram (Red Dwarf sitcom)
H Holy
H Home
H Homo- (Latin: human-taxonomic genus)
H Honda
H Honeywell Information Systems, Incorporated
H Horizontal (polarization)
H Horn (music)
H Hospital
H Hotel (aviation letter code)
H Høyre (Norwegian left wing party)
H Humidity
H Hundred
H Hungary (International Auto Identification)
H Hurricane(s)
H Husband
H Hyperphoria (condition of one eye being higher than the other)
H Hyundai (automobile brand)
H Kruskal-Wallis Test (statistics; analysis)
H Magnetic Field (physics)
H Metro Montreal (postal code designation, Canada)
H Planck's Constant (6.626 Ã 10^-34 joule-second)
H Sulfur Mustard (blister warfare agent)
H Undenominated United States Stamp (33 cents, introduced 10 Jan 1999)
H US DoT tire speed rating (130 mph)
H Winchester Repeating Arms Company (headstamp for rim-fire cartridges)
h Hecto