- half-element
- half-integer
- half-silvered
- halide
- halocarbon
- grounding transformer
- group bus
- guard arm
- gun
- Gunn device
- Gunn oscillator
- gyromagnetic
- h bomb
- H mode
- H vector
- H-line
- halide lamp
- Hall constant
- halocarbon compound
- halocarbon refrigerant
- halogen detection
- halogen refrigerant
- halogenated hydrocarbon
- hand generator
- handling
- hard component
- hard edges
- hard ice
- hard magnetic
- hardened glass
- hardening cabinet
- harmless
- harmonic
- harmonic analysis
- harmonic distortion
- harmonic factor
- harmonic input
- harmonic oscillator
- harmonic representation
- harmonic response
- harmonic signal
- harmonic state
- Haidinger fringe
- hair felt
- hair humidistat
- half life
- half-cell
- half-cooling
- half-decay
- half-disintegration
- Hall generator
- halocarbon coolant
- hard superconductor
- hard-wire
- harden
- hardening heat
- hardening room
- hardening temperature
- hardening tunnel
- hardness index
- harmless refrigerant
- harmonic fields
- harmonic frequency
- harmonic generator
- harmonic law
- harmonic loss
- harmonic tone
- harmonic trap
- Hartman generator
- Hartman number
- hay bridge
- hazardous temperature
- haze
- head-on
- heat endurance
- heat expansion
- heat extraction
- heat flow
- heat flux
- heat gain
- heat generation
- heat gun
- heat input
- heat lag
- heat lamp
- heat leak
- heat leakage
- heat losses
- heat output
- heat path
- heat reception
- heat rejection
- heat resistance
- heat shield
- heat sink
- heat storage
- heat transformation
- heat transmission
- heat transport
- heat treatment