An abbreviation sometimes used in British schools for "Craft, Design and Technology".
It covers a wide range of topics such as
- Metal work
- Wood work
- "Technology" - may involve building things out of metal or wood, but often computer-interfaced or more "cross-disciplinary"
- "Graphics" - technical design and drawing
- Sometimes the more traditional art lessons are also included under CDT (eg Painting and Drawing, Printing, Pottery etc)
The facilities needed to teach CDT can be quite expensive - decent public schools (which are private schools... never mind) may have multiple workshops with proper industrial lathes, milling machines, drill-presses etc. There has also been a trend over the last 15 years to introduce CAM systems (Computer Aided Machining) - for example, a software package which allows you to design something that a lathe can make, and then send it straight to a computer controlled lathe which automates the entire process.
Many schools will also offer CDT courses to GCSE or A-Levels.