- Cyanate
- Cyanate ester
- Cyanide
- Cyanoacrylate
- Cyanobacteria
- Cyanogen
- Cyanosis
- Cyclam
- Cyclic compound
- Cycling
- Cycloalkanes
- Cyclohexane
- Cyclooctatetraene
- Cyclooxygenase
- Cycloparaphenylene
- Cyclopentadiene
- Cyclotrons
- Cylinder
- Cylinder heads
- Cytochrome p450
- Cytokines
- Cytoplasm
- Czochralski method
- DAC
- DC
- DCVG
- DFT
- DLC
- DNA
- DNA polymerase
- DNA repair
- DNA sequencing
- DNP
- DOI
- DRI
- DSC
- DWR
- Dacite
- Dalton
- Dalton's law
- Dam removal
- Damage tolerance
- Damp
- Damp proofing
- Dampers
- Damping
- Dams
- Dandruff
- Dangerous goods
- Dangling bonds
- Darcy's law
- Dark energy
- Dark matter
- Data centers
- Data corruption
- Data set
- Data structures
- Database
- Davy lamp
- Dawsonite
- Daytime
- Daytime running lamps
- Dead zones
- Dean-Stark apparatus
- Debye length
- Debye model
- Decaffeination
- Decantation
- Decanters
- Decarburization
- Decay chains
- Decay products
- Decibels
- Decompression
- Decompression sickness
- Deconstruction
- Deep drawing
- Deep eutectic solvent
- Deep foundation
- Deep geological repository
- Definite matrix
- Deflection
- Defluoridation
- Defoamer
- Deforestation
- Deformation
- Deformation mechanisms
- Deformation monitoring
- Degree of polymerization
- Degrees of freedom
- Dehumidifier
- Dehydration
- Dehydration reaction
- Dehydrohalogenation
- Deicing
- Delamination
- Delayed neutrons
- Delta wings
- Delta-aminolevulinic acid dehydratase
- Deltahedra
- Dementia
- Demodulation
- Demolition
- Denaturation
- Dendrimers
- Dendritic
- Dendronized polymers
- Denitrification
- Density of air
- Dental composite
- Dental fluorosis
- Dental implants
- Dental plaque
- Denticity
- Dentin
- Depleted uranium
- Depolymerization
- Deposition
- Depressions
- Deprotonation
- Derailment
- Dermatitis
- Dermatology
- Derrick
- Desalination
- Descaling agent
- Desert rose
- Desiccants
- Desiccation
- Desiccator
- Design life
- Desktop computer
- Desorption
- Desquamation
- Desulfotomaculum
- Desulfovibrio vulgaris
- Desulfurization
- Detection limit
- Detergent
- Determinant
- Detonation
- Detritus
- Developable surfaces
- Device drivers
- Dew
- Dew point
- Dewatering
- Dexron
- Diabase
- Diabetes