contact_uuid is a database column name. ID is the corresponding attribute in CNT object.
You may want to have a look at the schema designer, available in the web screen painter (pdm_wsp.exe on sdm server, use the little hammer button). You can see every object, with its attributes, and the corresponding database name.
If you want to know the name of an object, just right click on a form in ServiceDesk, it'll show the name of the htmpl file being displayed.
On a contact detail page, right click shows you : "print form detail_cnt.htmpl" where cnt is the object name.
An change order will show "print form detail_chg.htmpl" and so on.
Have fun.