transitive verb
Definition 1
Complete, add, enter (all required or appropriate details, information, etc. in spaces provided in form or similar).
Source: Invertext
Context: Others [of the victims of the London terrorist bombings of 07/07/2005] had not yet filled in the forms and were only dimly aware of the [criminal injuries compensation] scheme.
Source: Financial Times 30/06/2006
Definition 2
Refill (hole, hollow, excavation, bomb crater, etc.).
Source: Invertext
Context: The city of Chicago has filled in hundreds of acres of Lake Michigan to create parkland that is much enjoyed by its citizens.
Source: Financial Times 30/03/2010 (letter from Edward W. Walbridge)