- dummy coil
- dump power
- drift speed
- drip tray
- drive motor
- driver element
- dropout
- dropwise condensation
- drum armature
- dry
- dry atmosphere
- dry ice
- duplicate test
- duplication
- duralumin
- dust dosimeter
- dust filter
- dust trap
- dynamic bias
- dynamic braking
- dynamic capacitance
- dynamic characteristic
- dynamic constant
- dynamic convergence
- dynamic dehumidifier
- dynamic electricity
- dynamic focusing
- dynamic impedance
- dry steam
- drying capacity
- drying temperature
- drying zone
- dual coordinates
- dual decay
- dual network
- dual-glazing
- duality
- duct arrangement
- duplex winding
- dust collector
- dust load
- dynamic similarity
- dynamical equilibrium
- dynamical viscosity
- dynamically balanced
- dynamometer relay
- dynamometry
- dynamostatic
- dynatron
- dyne
- dynode
- dysprosium
- E bend
- E cell
- e mode
- E vector
- E-capture
- ear
- earth current
- earth detector
- earth electrode
- earth leak
- earth return
- earth shield
- earth termination
- earth testing
- earthed system
- earthing inductor
- earthing reactor
- earthing transformer
- earthquake behaviour
- earthquake center
- earthy dolomite
- echelette grating
- echelon grating
- echo
- echo effect
- echo suppression
- echo suppressor
- echo-sounder
- eclipsing binary
- ebulliometer
- ebulliometry
- eccentric anomaly
- eccentric mirror
- echelon lens
- echo area
- echo cancellation
- echo canceller
- echo room
- economizer condenser
- edgeboard connector
- effect unit
- effective area
- effective chiller
- effective inductance
- effective section
- effective time
- effectively grounded
- efficient chiller