ISO 9000 VS. 9001?
ISO 9000 is a series, or family, of quality management standards, while ISO 9001 is a standard within the family. The ISO 9000 family of standards also contains an individual standard named ISO 9000. This standard lays out the fundamentals and vocabulary for quality management systems (QMS).
ISO 9000 Series of Standards
The ISO 9000 family contains these standards:
ISO 9001:2015: Quality management systems - Requirements
ISO 9000:2015: Quality management systems - Fundamentals and vocabulary (definitions)
ISO 9004:2009: Quality management systems – Managing for the sustained success of an organization (continuous improvement)
ISO 19011:2011: Guidelines for auditing management systems
Every certified organization should have the top two on this list. I highly recommend also having a copy of
ISO/TS 9002:2016: Quality management systems -- Guidelines for the application of ISO 9001:2015.
This document provides "plain English" guidance on the intent of the requirements in ISO 9001:2015, with examples of possible steps an organization can take to meet the requirements. It does not add to, subtract from, or in any way modify those requirements. ISO/TS 9002:2016 does not prescribe mandatory approaches to implementation, or provide any preferred method of interpretation. It gives insight as to what the authors meant when the standard was written.