Internal & external audits: first-, second-, and third-party audits. 1  A first-party audit is performed within an organization to measure its strengths and weaknesses against its own procedures or methods and/or against external standards adopted by (voluntary) or imposed on (mandatory) the organization.
Precursor (chemistry) In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry, the term precursor often refers more specifically to a chemical compound preceding another in a metabolic pathway, such as a protein precursor. 1 Illicit drug precursors.
a person or thing that precedes, as in a job, a method, etc.; predecessor. 2. a person, animal, or thing that goes before and indicates the approach of someone or something else; harbinger: The first robin is a precursor of spring.