| H | Hydrogen; Henry (unit of inductance) |
| H | Henry |
| h | Hybrid |
| H | Magnetic field intensity |
| H | Magnetizing flux |
| HAC | Hands-free Add on Circuit |
| HAP | Hazardous Air Pollutant |
| HARM | High-speed Anti-Radar Missile |
| HASL | Hot Air Solder Leveling |
| HAST | Highly Accelerated Stress Testing |
| HAZCOM | Hazard Communication Standard |
| HB | Horizontal Bridgman (crystal) |
| HBT | Heterojunction Bipolar Transistor |
| HCI | Hot Carrier Injection |
| HCMOS | High-density Complementary Metal-Oxide Semiconductor |
| HCP | Hexagonal Close Packed |
| HCS | Hot-Carrier Suppressed |
| HCT | High-speed CMOS TTL compatible |
| HD | Hard Disc |
| HD | High Definition |
| HD | High Density |
| HDCP | High Bandwidth Digital Content Protocol |
| HDD | Hard Disc Drive |
| HDL | Hardware Description Language |
| HDMI | High Definition Multimedia Interface |
| HDP | High Density Plasma; Hydrostatic Deformation Potential |
| HDPE | High-Density PolyEthylene |
| HDSD | Hydrogen Defect Shallow Donors |
| HDSL | High (bit rate) Digital Subscriber Line |
| HDTV | High Definition Tele Vision |
| HEMT | High Electron Mobility Transistor |
| HEPA | High-Efficiency Particulate Air |
| HF | High Frequency |
| HF | Hydrofluoric acid; High Frequency |
| HFC | Hybrid Fiber/Coax |
| HFD | High Frequency Doppler |
| HFET | Heterojunction FET |
| HFI | HyperFine Interaction |
| HGF | Horizontal Gradient Freeze |
| HGL | Hewlett-Packard Graphics Language image format |
| HIBS | Heavy Ion Backscattering Spectrometry |
| HIC | Hybrid Integrated Circuits |
| HID | Human Interface Devices |
| HIGFET | Heterojunction Insulated Gate FET |
| HIPOX | HIgh-Pressure OXygen |
| HIPPI | High Performance Parallel Interface |
| HITS | Head-End-in-the-Sky (AT&T) |
| HLF | Horizontal Laminar Flow |
| HMAC | Keyed-Hash Message Authentication Code |
| HMIS | Hazardous Materials Inventory Statement |
| HMMP | Hazardous Materials Management Plan |
| HMOS | High-performance MOS; High-density MOS |
| HMT | Hand Micro Telephone |
| HMT | Hindustan machine Tools |
| HOMER | Hazardous Organic Mass Emission Rate |
| HOMO | Highest Occupied Molecular Orbital |
| HOPG | Highly-Oriented Pyrolitic Graphite |
| HP | High Purity |
| HPA | High Power Amplifier |
| HPC | High Performance (micro)Controller |
| HPCC | High Performance Computing and Communicating |
| HPEM | Hybrid Plasma Equipment Model |
| HPF | High Pass Filter |
| HPI | High-Pressure Isolation |
| HPIB | Hewlett-Packard's Instrument Bus |
| HPL | High Performance Logic |
| HPLC | High-Performance Liquid Chromatography |
| HPM | Hazardous Production Materials; High Power Microwave; High Purity Metal |
| HPNA | Home Phoneline Network Alliance |
| HPV | High-Pressure Vent |
| HRA | Human Reliability Analysis |
| HREELS | Hi-Res Electron Energy Loss Spectroscopy |
| HREM | Hi-Res (Transmission) Electron Microscopy |
| HRPT | High Resolution Picture Transmission |
| HRS | Holographic Readout System |
| HRTEM | Hi-Res Transmission Electron Microscopy |
| HSCC | High-Level Serial Communication Controller |
| HSCSD | High Speed Circuit-Switched Data |
| HSCX | High-Level Serial Communication Controller Extended |
| HSDS | High Speed Data System |
| HSM | High Side Mixing |
| HSMS | High Speed Message Services |
| HSRRSS | High Spatial Resolution Remote Sensing Satellite |
| HT | High Tension |
| HTCC | High Temperature Cofired Ceramic |
| HTCS | High Tc (critical temperature) Superconductors |
| HTE | High Temperature Electronics; High Temperature Elongation |
| HTH | Head-To-Head |
| HTL | High-Threshold Logic |
| HTML | Hyper Text Markup Language |
| HTO | High-temperature Oxidation |
| HTR | High Temperature Reactor |
| HTRB | High-temperature Reverse Bias |
| HTSC | High Temperature Super Conductor |
| HTTP (http) | Hyper Text Transfer Protocol |
| HTU | Height of Transfer Unit |
| HUPW | Hot UltraPure Water |
| HV | High Voltage |
| HVEM | High-Voltage Electron Microscopy |
| HV-SLIC | High Voltage Subscriber Line Interface Circuit |
| HWHM | Half Width at Half Maximum |
| HY | Hybrid |
| He | Helium |
| Hg | Mercury |
| hp | horse power |
| H-pol | Horizontal Polarization |
| https | HyperText Transfer Protocol over SSL |
| Hz | Hertz |
