Skeleton code is basically a preset of code that can be seen as a starting point.
Whenever you would start of a new project, majority of us have one or more "skeleton code" we include. To ease the burdon when starting fresh.
Skeleton code is usually the outmost basic you would need to get you started.
Example: http://csswizardry.com/2011/01/the-real-html5-boilerplate/#html5-boilerplate