- Doppler
- dormant
- Dortmund method
- dosc
- dot crawl
- dot punch
- dot signal
- dotting needle
- double acting
- double acting cylinder
- double acting hinge
- double acting rotary engine
- double action piston
- double angle milling cutter
- double arm press
- double back geared
- double barrel
- double beam tube
- double bell insulator
- double bladed cutter
- double bracket
- double buffing machine
- double cantact breaker
- double card
- double chain retarder
- double cleaner shoe
- double clutching
- double column hydraulic planer
- double compression
- double contact bulb
- double control
- double cover butt joint
- double cup wheel
- double cut plow
- double cylinder gig
- double deck bus
- double deck classifier
- double decker
- double delta connection
- double diffusion epitaxial plane
- double disk cultivator
- double doffer condenser
- double drum air driven hoist
- double edge crack
- double end knife colter
- double ended clipper
- double ended wrench
- double extraction condensing
- double feed distributor with partitioned hopper
- double filament bulb