When reading about SQL I've come across the term 'slot'. For example, in a DBCC error message you may get something like this which references slot 0:
Page (1:157), slot 0 in object ID 2121058592, index ID 0, partition ID 72057594038517760, alloc unit ID 72057594042515456 (type "In-row data"). Column "col2" value is out of range for data type "datetime". Update column to a legal value.
I'm pretty sure it's something to do with the physical location but I can't find a definition anywhere which gives its exact meaning.
Any ideas?