C3

C3, C-3, C.3, C03, C.III or C-III may refer to:

==Life and biology== C3 carbon fixation in plants C3-convertase, an enzyme Complement component 3, a protein of the innate immune system Apolipoprotein C3, a human very low density lipoprotein ATC code C03 Diuretics, a subgroup of the Anatomical Therapeutic Chemical Classification System Castavinol C3, a natural phenolic compound found in red wines Cytochrome-c3 hydrogenase, an enzyme Haplogroup C-M217, called C3 in older publications In human anatomy, C3 may refer to: Cervical vertebra 3, one of the cervical vertebrae of the vertebral column Cervical spinal nerve 3 Clinical Cell Culture, a medical technology company C03, Malignant neoplasm of gum ICD-10 code C3 Collaborating for Health, a health-promotion NGO C3: an EEG electrode site according to the 10-20 system