"The open window" in Saki's "The Open Window" symbolizes deception as Vera fabricates a story about her family, using the open window to mislead and play a prank on Framton Nuttel.
The passage you're referring to from Saki's "The Open Window" is likely a reference to the time mentioned in the story. In this context, "the open window" is not explicitly referring to a specific time of day but rather to a specific event that occurred in the past.
The open window becomes a symbol of deception, as the main character, Framton Nuttel, is told a fictional story by Vera, the young girl in the story. Vera's tale involves her aunt's husband and brothers going out through the open window on a hunting trip three years ago, never to return.
However, it is later revealed that the story is a fabrication meant to amuse Vera and play a prank on Framton. So, "the open window" in this context serves as a literary device to mislead the reader and the character in the story.