This glossary is a list of agreed upon terms with precise definitions, the source (if directly adopted or based on an industry publication), and a list of synonyms. A major barrier that emerged immediately during the first Aerospace & Defense PLM Action Group (AD PAG) multi-view BOM workshop was the inability of the assembled experts from the member companies to effectively communicate due to their use of different terms for similar concepts (or sometimes even use of the same term for contradictory concepts). The goal of the glossary is to support effective communication throughout the aerospace and defense industry and to promote incorporation of common language within future PLM solution provider offerings and documentation.