What does Hh stand for?

Hands High - Equine term (TED)

Hemopoietic Histocompatibility (STED)

Heterozygous - Medicine (EDAA)

Hands High - Equine term (TED)

Disney Vacation Club Hilton Head Resort - Disney (DIS)

Double Hard - Pencil leads

Extra Hard - Pencil leads

Fairchild/Republic - ICAO aircraft manufacturer identifier (ICAO)

Habitat for Humanity (EA)

Haiti (SAUS)

Half Hard - Metallurgy

Half Hardy - Horticulture

Halogenated hydrocarbons (SAUS)

Halothane Hepatitis - Medicine (DMAA)

Halothane Hypoxia - Medicine

Hamish Hamilton - Publisher - British

Hamizrah Hehadash - Jerusalem - A publication (BJA)

Hampshire Hunt - British

Handhole (AAG)

Hands - Units of measure, especially for the height of horses

Hanging Handset - Telecommunications (TEL)

Hansestadt Hamburg - German license plate city code

Happy Humpers (EA)

Harbridge House Europe (SAUO)

Hardesty and Hanover, L.L.P. - Commercial firm

Hard of Hearing

Hargraves-Haserick (SAUO)

Harvest Help - An association - British (EAIO)

Has Had - Telegraphy (PCTE)

Hashomer Hatzair (EA)

Haunt Hunters (EA)

Hawaii State Library System, Honolulu, HI - Library symbol - Library of Congress (LCLS)

Hayward and Hazelton's United States Circuit Court Reports - District of Columbia - A publication (DLA)

Hazardous Hydrocarbons (SAUS)

Head, Head - Coin-tossing possibility

Head-Holmes - Syndrome - Medicine (DB)

Heading to Heading (VLIE)

Headlamp Housing - Automotive engineering

Head-to-Head - Polymer structure

Healthy - Medicine (EDAA)

Healthy Hemophiliac - Medicine (DMAA)

Heard of Hearing (SAUS)

Heavily Hinged (SAUS)

Heavy Hail (SAUS)

Heavy Helicopter - Military (VNW)

Heavy Hinged - Philately

Heavy Hole (SAUS)

Heavy Hydrogen

Heil Hitler - Political organization - British

Helen Hunt Jackson - American novelist, 1830-1885 - Initials used as pseudonym

Hellhole

Hemmets Haerold - Record label - Sweden

Henderson and Haggard - Inhaler - Medicine (DAVI)

Hepatic Hydatidosis - Medicine (MELL)

Herbig-Haro - Astronomy

Hereditary Haemochromatosis - Medicine

Here's Health - Exhibition - British

Herfindahl-Hirschman - Economic indicator

Herman Hospital - Houston, TX

Hermann Hospital (SAUS)

Her (or His) Honour (SAUO)

Hertfordshire Hunt - British (ROG)

Hesketh Hubbard Art Society (SAUO)

Hetch Hetchy Railroad (IIA)

Hiatal Hernia - Medicine

High Heels - Doll collecting

High-Powered, Nondirectional Radio Homing Beacon - Navigation

Himmelberger-Harrison Manufacturing - Federal Railroad Administration identification code

His - or Her Highness

His Holiness

His Honour - British (ADA)

Historical Handbook

Hitchhiker (SAUS)

Hodgson's Horse - British military (DMA)

Hogarth - H. and Sons - Steamship line (MHDW)

Hogshead (DNAB)

Hold Harmless (OICC)

Holding Hands (SAUS)

Holidays for Humanity - An association (EA)

Holistic Health - Medicine (DAVI)

Home Health - Medicine (DAVI)

Home Help - Medicine

Hommel AG - Switzerland - Research code symbol

Homonymous Hemianopsia - Ophthalmology

Homozygous - Medicine (EDAA)

Hooper Holmes, Inc. - AMEX symbol (SPSG)

Horizontal-Horizontal (ACAE)

Hour (SAUS)

Hour Hand - Clocks (ROG)

Household

Hughes Helicopters (MCD)

Human Hair - Doll collecting

Humbert Humbert - Character in Vladimir Nabokov's "Lolita"

Hunter-Hurler - Syndrome - Medicine (DB)

Hydroxyhexamide - Organic chemistry (MAE)

Hydroxyhexenal - Organic chemistry

Hy Hunter - NCIC firearms make code (NCIC)

Hyperactive Help - Australia

Hypergastrinemic Hyperchlorhydria - Medicine (DB)

Hypnogogic Hallucinations - Medicine

Hypogonadism - Endocrinology (DAVI)

Hypogonadotrophic - Endocrinology (DAVI)

Hyporeninemic Hypoaldosteronism - Endocrinology

Les Hieroglyphes Hittites - A publication (BJA)

Rotary-Wing Air-Sea-Rescue Aircraft - Navy symbol (MUGU)

Somali Airlines - ICAO designator (AD)