CHDK Abbreviation
CHDK – Canon Hacker’s Development Kit.
The CHDK hack, which adds a lot of features to your Powershot camera, is a very specific one. It only works on some Canon Powershot cameras. It’s free to download and use, and newer versions that support more recent Powershot models are being released all the time. CHDK compatible scripts like Motion Detection and other cool stuff are available for you to download from the CHDK website. Check the CHDK Wiki for more information.
As a note, I should probably tell you that the CHDK is in no way related to Canon, the company.