Glossary - initial structure and definitions

[balteravishay]

This is still WIP, comments are very welcome. specifically interested in getting some feedbacks about:

• Thoughts about the table's structure: columns Source1, Source2, Source3 vs. columns with specific source names (NIST, CVE.org, OWASP, etc.).
• Quite a few NIST definitions are actually empty (for instance https://csrc.nist.gov/glossary/term/cert). should I remove those?
• What other glossary-sources would be good to quote in additional columns?
• Some terms I could not find any source for. please comment if you have such source in mind, or would like to propose a definition for, or if it should be perhaps removed.