A small person. ie. small + midget = a smidget. Originated in a grade 8 class in Ajax Ontario from a boy named John to a particularly short girl named Nicole. The name stuck and eventually became somewhat of a nickname for her. It was also later used as a "camp name" 3 or 4 years later when she was a camp counsellor. Some times spelled "smidgette". It is also sometimes shortened to "smidgie".
"Our counsellor smidget, she really liked to fidget and we didn't know what to do" "Smidget, get in my backpack!"