Filler

Filler is the use of endless description in order to make a book longer. Filler can take on many forums, such as:
 * Describing every day of a 1000-mile trek; where the characters slept, what they ate, etc.

It is generally frowned upon as it makes the story boring. However, in NaNoWriMo, where every word counts, it is often less frowned upon.