- direct acting
- direct contact
- direct drive
- direct expansion
- direct process
- direct sale
- direction board
- direction finder
- diapir
- diaspore
- diastereomer
- diazo compound
- dibhole
- dichromate
- didymium
- dielectric
- diesel fuel
- diethnolamine
- differential pressure
- differentiated dike
- differentiation
- diffusiometer
- diffusion apparatus
- diffusion oven
- difluence step
- diformyl
- digester
- digestion
- digitalein
- directional drilling
- directional transmission
- directionality
- dirty sand
- dirty weather
- disability
- disablement insurance
- disacidified tar
- disassembly
- disc valve
- discharge air
- discharge chamber
- discharge liquor
- discharge pressure
- discharge ratio
- discharge temperature
- discharge terminal
- disconformity
- disconnected
- disconnector
- discovery work
- disilicate
- disintegrated
- disintegrated rock
- disintegrator
- disjointing
- disjunctive rock
- disk valve
- dislocated
- dislocation
- dislocation breccia
- dislocation debris
- dislocation kink
- dislocation velocity
- dismantling flange
- dispatch
- dispatch center
- dispatch sheet
- dispense
- dispersed part
- dispersing agent
- dispersion fuel
- dispersion medium
- displaced mass
- disseminated
- dissociate
- dissolved
- distance bolt
- distemper paint
- disthene
- distillating tube
- distillation residue
- distillation temperature
- distorted
- distribution license
- disturbed area
- directional valve
- directional well
- dirt
- dirtied rock
- disc clutch
- discharge coefficient
- discharge head
- discharge hydrograph
- discharge line
- discharge pipe
- discharge port
- discontinued
- discordance
- discordant
- discovery well