What does HO stand for?

Airways International - ICAO designator (AD)

Charterair - ICAO designator (AD)

Habitual Offender (SAUS)

Haem Oxygenase - An enzyme

Hale Observatories - Formerly, Mount Palomar and Mount Wilson Observatories

Halogenated Organic Carbons (GNE)

Hand-Operated (SAUS)

Hand Orthosis - Medicine

Handout (FOTI)

Hand Over (MCD)

Hang Over (ACAE)

Hardened in Oil (SAUS)

Hard Overhung Balancer (SAUS)

Hardware Operation (SAUS)

Harmonic Oscillator

Hazardous Organics - Environmental science

Head Office

Headquarters Offices (EEVL)

Health Occupations (SAUO)

Hearing Office (SAUS)

Hearing Officers (SAUO)

Heel Off Ground - Medicine

Heme Oxygenase (SAUS)

Herbarium of the Tasmanian Museum and Art Gallery (SAUO)

Hertzian Oscillator (SAUS)

Heterotopic Ossification - Osteology

High Oblique - Aerospace

High Order - Computer science (OA)

High Output - Automotive engineering

High Oxygen (MAE)

Hip Orthosis - Medicine

Hippocratic Oath (MELL)

History Office (MCD)

Hochofen - Blast Furnace (GIS)

Hof - Saale - German license plate city code

Hoist

Hold - Shipping (DS)

Hold - Telegraphy (PCTE)

Holding Out - Cashier fraud

Hold Over (SAUS)

Holdover - Theater

Holt-Oram - Syndrome - Medicine (DB)

Holy Day of Obligation - Roman Catholicism

Holy Orders (ROG)

Home Office - British

Home Oil Co. (EFIS)

Home Only - British military (DMA)

Homeowners' - Insurance

Homestead

Homologous (MELL)

Honduras - GeoNet country code (GEON)

Honduras - Federal Information Processing Standard (FIPS) country code (GEON)

Honduras Outreach - Association (EA)

Hook Opening (SAUS)

Horizontally Opposed - Automotive engineering

Horizontal Output (IAA)

Hostilities Only - Applied to men who joined for duration of war only - Navy - British - World War II

Hotel (ROG)

Hours of Operation

House

Housekeeping Operation (SAUS)

House Officer

Housing Operations (SAUO)

Houston Oil Trust - AMEX symbol (COMM)

Howland Island - NCIC American territory possession code (NCIC)

Human Operator (IAA)

Hunting Oscillator (IAA)

Hybrid Orbital (SAUS)

Hydraulic Operator (NRCH)

Hydrogen-Oxygen - NASA (NASA)

Hydrographic Office - Terminated, 1963; later, NOO - Navy

Hyperbaric Oxygen - Medicine

Hyperostosis - Medicine (MELL)

Observation Helicopter

Observed Height (SAUS)

ProAirshow, LLC - Air show performer (ASPC)

Service Available to Meet Operational Requirements - ICAO (FAAC)

held over (SAUS)

heterothallic (SAUS)

homothallism (SAUS)

Honduras - MARC country of publication code - Library of Congress (LCCP)

Honeycomb Lung - Medicine (EDAA)

Hydroxy - As substituent on nucleoside - Also, oh - Biochemistry

Holmium - Chemical element

Homobonus de Cremona - Deceased, 1272 - Authority cited in pre-1607 legal work (DSA)

Horse (DMAA)

Hosea - Old Testament book (BJA)

Hostiensis - Deceased, 1271 - Authority cited in pre-1607 legal work (DSA)

Observed Altitude