Definition of Terms

ISO standards rely on some foundational terms.
Here are some that get confused:
Nonconformity: non-fulfillment of a requirement. Failing to meet a product characteristic, regulatory requirement, company policy, safety rule, QMS directive, etc.; (whether, or not, it is immediately detected.)
Correction: Action to eliminate a detected nonconformity. Example: re-working or replacing part. Notice, this action does nothing to resolve the cause of the non-conformity, but is done to keep the customer happy.
Corrective Action: Action(s) to eliminate the cause of a nonconformity and to prevent recurrence. Learning the system flaw that created the event: e.g. a gap in information, method, materials, etc; and revising the process accordingly.
Preventive Action: An action to eliminate the cause of a potential nonconformity or other potential undesirable situation. For instance, moving a cable from a walkway before someone trips.