noun

• (informal) A doctor.
• (informal, usually in the plural) A document, especially (in professional jargon) a piece of technical documentation or legal evidence.
• (informal) A documentary.
• A nickname for a medical doctor, a person with an advanced educational degree, or a learned person.
• (slang, United States military) A common form of address for combat medics, especially naval hospital corpsmen.
• (slang, usually in the plural) A Doc Marten shoe or boot.
• Clipping of doctorate. [The highest degree awarded by a university faculty.]
• Initialism of drug of choice. [(law, narcotics) The particular substance, usually illicit, to which a person is addicted.]
• Initialism of Department of Corrections.
• (sciences) Initialism of dissolved organic carbon.