3 useful usability glossary

Rachel mentioned some concept of usability in her comment on my last post. When I tried to find out the meaning of those terms I found some good glossary that might be good for study:

• Interaction Design Encyclopaedia
  A growing encyclopaedia on interaction design; the articles not only explain usability terms and issues, but also provide a detailed description of their use in modern design.
  
  
• Usability First Glossary: Alphabetical Index
  One of the largest usability glossaries with hundreds of articles about usability-related issues.
  
  
• Usability Glossary
  Usability 101. Usability Glossary from the Information Technology Systems & Services of the University of Minnesota Duluth.