- directed set
- directed trihedral
- direction angle
- direction coefficient
- direction completion
- direction cosine
- direction key
- dielectric storage
- Difference equation
- differentiable manifold
- differential delay
- differential method
- differential parameter
- differential structure
- differential variety
- differentiate
- differentiator
- difficult
- diffuse
- diffused resistance
- diffuser
- diffusion rate
- digamma function
- digging bar
- digit capacity
- digit compression
- digit count
- digit duration
- digit period
- digit place
- digit punch
- digit track
- digital
- digital calculation
- digital camera
- digital cassette
- digital certificate
- digital channel
- digital clock
- digital communications
- digital comparator
- digital computation
- digital computer
- digital conversion
- digital counter
- digital data
- digital display
- digital divider
- digital document
- digital drum
- Digital Equipment
- digital line
- digital link
- digital meter
- digital modulation
- digital monitor
- digital output
- digital picture
- digital printer
- digital process
- digital radio
- digital recorder
- digital recording
- digital representation
- digital resolution
- digital signature
- digital simulation
- digital sort
- digital speech
- digital storage
- digital subtracter
- digital value
- digital video
- digital watch
- direction parameter
- direction ratio
- directional
- directional derivative
- directional field
- directional filter
- directional keys
- directional stabilizer
- director
- director sphere
- directory
- directory key
- directory name
- directory structure
- directory window
- directrix curve
- DirectX
- disable port
- disabled interrupt
- disassociate
- disassociated
- discard priority
- discarded cell
- discharge counter
- discharge curve
- discharge diagram