While these terms are often used interchangeably, a nonconformity is a more precise term and is the one formally used in ISO 9001 to describe instances of noncompliance with the standard's requirements. Nonconformance, on the other hand, is a broader term that can encompass various types of failures to meet quality criteria.

Nonconformity is also referred to as nonconformances, non-conformities, or simply NCs throughout the industry. According to the International Standards Organization (ISO), "conformity" is the fulfillment of a requirement. The term "conformance" is obsolete. The term used is "conformity" (and "nonconformity").

Nonconformance typically refers to deviations in products or processes from specified standards, while nonconformity often describes behavior or actions not aligning with social norms.

Nonconformance refers to a failure to meet specified standards or expectations. It signifies that a product, service, or process does not align with the relevant company’s requirements. On the other hand, noncompliance refers specifically to a violation of laws and regulations that have been set by external governing or regulatory bodies.