China 
Africa 
- Cataclasite
- Cataclastic rock
- Catadioptric system
- Catalan numbers
- Catalan solids
- Catalase
- Catalog
- Cataloging
- Catalpol
- Catalyst poisoning
- Catalyst support
- Catalysts
- Catalytic chain transfer
- Catalytic combustion
- Catalytic converter
- Catalytic cycles
- Catalytic oxidation
- Catalytic reforming
- Catalytic triad
- Catamarans
- Cataract surgery
- Cataracts
- Catastrophe modeling
- Catastrophe theory
- Catastrophic cancellation
- Catastrophic failure
- Catastrophic injury
- Catastrophism
- Catchment hydrology
- Catechin
- Catechol
- Catechol dioxygenase
- Catechol oxidase
- Catechol-o-methyltransferase
- Catecholaminergic
- Catecholamines
- Categorical distribution
- Categorical variables
- Categorization
- Category theory
- Catenanes
- Catenary
- Catenin
- Catenoid
- Cathelicidin
- Cathepsin
- Cathepsin k
- Catheter ablation
- Catheterization laboratory
- Catheti
- Cathode ray
- Cathodic
- Cathodic arc deposition
- Cathodic protection
- Cathodoluminescence
- Catio3
- Cation diffusion facilitator
- Cationic polymerization
- Cativa process
- Cattierite
- Cauchy distribution
- Cauchy elastic material
- Cauchy momentum equation
- Cauchy problem
- Cauchy sequences
- Cauchy stress tensor
- Cauda equina
- Cauda equina syndrome
- Caudal
- Caudate nucleus
- Caulk
- Caulking
- Caulobacter
- Caulobacter crescentus
- Causal analysis
- Causal filter
- Causal graphs
- Causal inference
- Causal models
- Causal structure
- Cause
- Cause of autism
- Cause of death
- Caustic
- Caustics
- Cauterization
- Cave-dwelling
- Cave-ins
- Caveolae
- Caveolin
- Caves
- Cavitand
- Cavitation
- Cavitation number
- Cavity magnetron
- Cavity optomechanics
- Cavity quantum electrodynamics
- Cavity resonator
- Cavity walls
- Cayley graphs
- Cayley transform
- Cbl
- Cd11c
- Cd137
- Cd25
- Cd45
- Cd63
- Cd80
- Cd86
- CdTe
- Cdma2000
- Cecal
- Cefalexin
- Cefixime
- Cefotaxime
- Cefuroxime
- Ceiling
- Ceiling effect
- Ceiling fans
- Celadonite
- Celastrol
- Celeron
- Celestial equator
- Celestial sphere
- Celestine
- Celiac artery
- Celiac disease
- Cell
- Cell adhesion
- Cell adhesion molecules
- Cell bank
- Cell cortex
- Cell count
- Cell counting
- Cell culture
- Cell culture assays
- Cell cycle analysis
- Cell damage
- Cell death
- Cell decomposition
- Cell disruption
- Cell division
- Cell encapsulation
- Cell envelope
- Cell fate
- Cell fusion
- Cell junctions
- Cell mechanics
- Cell membrane
- Cell migration