China 
Africa 
- Cryptococcosis
- Cryptocrystalline
- Cryptocurrency
- Cryptogram
- Cryptographic hash functions
- Cryptographic primitives
- Cryptographic protocols
- Cryptography
- Cryptography standards
- Cryptojacking
- Cryptomelane
- Cryptonote
- Cryptorchidism
- Cryptosporidiosis
- Cryptosystem
- Crystal chemistry
- Crystal engineering
- Crystal filter
- Crystal growth
- Crystal habit
- Crystal monochromator
- Crystal oscillator
- Crystal plasticity
- Crystal structure
- Crystal structure prediction
- Crystal systems
- Crystal violet
- Crystalline silicon
- Crystallinity
- Crystallins
- Crystallites
- Crystallization
- Crystallographic databases
- Crystallographic defects
- Crystallographic point groups
- Crystallography
- Crystals
- Ctbp1
- Cubanite
- Cube
- Cube roots
- CubeSats
- Cubic centimetre
- Cubic crystal system
- Cubic equations
- Cubic equations of state
- Cubic feet
- Cubic graph
- Cubic inch
- Cubic metre
- Cubic metres per second
- Cubic polynomial
- Cubic spline
- Cubic yards
- Cubic zirconia
- Cubital fossa
- Cubital tunnel
- Cubital tunnel syndrome
- Cubits
- Cuboctahedron
- Cuboid
- Cuboid bone
- Cuckoo filter
- Cuckoo search
- Cucurbituril
- Cue
- Cue validity
- Cues
- Cullet
- Cullin
- Culm
- Cultural algorithms
- Culture
- Culture plate
- Cultured meat
- Culverts
- Cumene
- Cumene hydroperoxide
- Cummingtonite
- Cumulants
- Cumulates
- Cumulene
- Cun
- Cuneiform bones
- Cunningham correction factor
- Cup holders
- Cupferron
- Cupola furnace
- Cupolas
- Cuprammonium rayon
- Cuprates
- Cupriavidus metallidurans
- Cupriavidus necator
- Cuprite
- Cupronickel
- Cups
- Cupula
- Cupy
- Cura
- Curcumin
- Curcuminoids
- Curdlan
- Cure
- Curie
- Curie temperature
- Curing
- Curiosity
- Curiosity Rover
- Curium
- Curl
- Curli
- Current clamps
- Current conveyor
- Current crowding
- Current density
- Current limiting
- Current loop
- Current meter
- Current mirror
- Current reality tree
- Current sense amplifier
- Current sensing
- Current sensor
- Current sheets
- Current sources
- Current transformer
- Current-feedback operational amplifier
- Current-mode logic
- Current-sense amplifier
- Curse of dimensionality
- Cursor
- Curtailment
- Curtain coating
- Curtain walls
- Curtius rearrangement
- Curvature
- Curve fitting
- Curve resistance
- Curve sketching
- Curve tracer
- Curve25519
- Curved mirrors
- Curved space
- Curvelet
- Curves
- Curvilinear
- Curvilinear coordinates
- Curvilinear motion
- Cushioning
- Cuspate forelands