When revealing the times when it is appropriate to speak louder, be able to play, and use other rooms in the house, Anne Frank (from The Diary of Anne Frank) refers to this time as "freedom after five." At five o'clock, all of the factory/warehouse workers leave for the day. As a result, the children no longer have to worry about making too much noise or interrupting the workers with their playing. They are free to play as children do and explore the offices and other rooms (Anne's "Secret Annexe").
Anne tells of Bep's arrival signaling their "nightly freedom." The children case the cats, go into offices they are not supposed to be in, all while dinner is begun. Three taps on the walls signals dinnertime. Essentially, the freedom after five is a time where Anne is allowed to remember that she is still a child. After five, Anne is allowed to play and explore as normal children do. This time is special for her because it allows her the normalcy needed in her life.