- Completely randomized design
- Complex
- Complex cells
- Complex organism
- Complex partial seizure
- Complex partial status epilepticus
- Complex post-traumatic stress disorder
- Complex regional pain syndrome
- Complex training
- Complexation
- Complexin
- Complexion
- Compliance gaining
- Complications
- Complications of diabetes
- Complications of hypertension
- Complications of pregnancy
- Composite materials
- Composite resin
- Composting
- Composting toilets
- Compound 48-80
- Compound analgesics
- Compound heterozygosity
- Compound muscle action potential
- Compounding
- Comprehensive geriatric assessment
- Comprehensive sex education
- Compressed air
- Compressed sensing
- Compression fracture
- Compression garment
- Compression therapy
- Compressor
- Compton scattering
- Compulsions
- Compulsive behavior
- Compulsive buying
- Compulsive hoarding
- Compulsive overeating
- Compulsive personality disorder
- Compulsive sexual behaviour disorder
- Compulsory sterilization
- Computational biology
- Computational chemistry
- Computational immunology
- Computational neuroscience
- Computed radiography
- Computed tomographic angiography
- Computed tomography angiography
- Computer aided drug design
- Computer assisted surgery
- Computer assisted tomography
- Computer vision syndrome
- Computer-aided diagnosis
- Computer-aided drug design
- Computer-assisted interventions
- Computer-assisted orthopedic surgery
- Computer-assisted surgery
- Computerized adaptive testing
- Computerized axial tomography
- Conalbumin
- Conantokins
- Conation
- Conatus
- Conbercept
- Concanavalin A
- Concatemers
- Concealer
- Concentration effect
- Concentration gradient
- Concept analysis
- Concept drift
- Concept learning
- Concept mapping
- Conception
- Conceptus
- Concerted Evolution
- Concha bullosa
- Concoctions
- Concordance
- Concordance Correlation Coefficient
- Concordant pairs
- Concussion
- Condensation
- Condensation particle counter
- Condensed tannins
- Condensers
- Condensing osteitis
- Conditional distribution
- Conditional probability
- Conditional variance
- Conditioned emotional response
- Conditioned place preference
- Conditioned reflex
- Conditioned response
- Conditioned stimulus
- Conditioned taste aversion
- Conditioners
- Conditioning
- Condolences
- Condom catheter
- Condoms
- Conduct disorder
- Conduct disorders
- Conduction aphasia
- Conductive hearing loss
- Conductive polymers
- Conductivity
- Conduritol
- Condylar
- Condylar hyperplasia
- Condyles
- Condyloid process
- Condyloma
- Condyloma acuminatum
- Cone beam computed tomography
- Cone beam reconstruction
- Cone cell
- Cone dystrophy
- Cone of light
- Cone opsin
- Cone rod dystrophy
- Cone-beam computed tomography
- Conessine
- Confabulation
- Confidentiality
- Confined placental mosaicism
- Confined space
- Confinement
- Confirmation bias
- Confirmatory factor analysis
- Confirmatory trial
- Confluence of sinuses
- Confluent and reticulated papillomatosis
- Confocal laser scanning microscopy
- Confocal microscopy
- Conformation
- Conformational change
- Conformational entropy
- Conformational epitope
- Confounders
- Confounding factors
- Confounding variables
- Confusion
- Confusion Assessment Method
- Confusional arousal
- Congeners
- Congenic
- Congenic strains