Consider these cases: - The sun is shining. (the only sun) - The airport is closed due to bad weather. (the only airport of interest - the closest airport) - It's hot. Please open the door. (the only door of a small room; the closest door of a large room) - It's hot. Please open a door. (one door of multiple doors) ''BRIAN ROBESON stared out THE window of THE small plane at the endless green northern wilderness below. The meaning as understood by a native speaker: ''BRIAN ROBESON stared out THE window [that was beside him] of THE small plane [that he was flying in] at THE endless green northern wilderness [that was] below.

Why is "the" used in this sentence? Why does the author use "the" in this sentence? It's in perfect alignment with the rules of English. Authors use the words they do to convey meaning. The character, Brian, is on one plane beside one window, and using "the" puts the reader in Brian's place. Using "a" would describe the situation from afar.

It’s a common use, in English. ‘A’ would be ‘any random window in the plane.’ ‘THE,’ in this case, is understood to mean, ‘the window beside his seat,’ or ‘his’ window in that plane, unless we are told otherwise. But, I agree. It’s confusing.