1. Indicates a cause or reason: “in that, since, because.”
Note: No de and kara (#15, II-1) differ in two ways: first, no de usually indicates a more objective cause or reason, kara a more subjective one; thus kara is often used in sentences involving prohibitions, commands, and questions; second, in sentences otherwise identical, no de lends a more polite tone.
Kuruma no jiko ga atta no de, michi ga konde imasu.
Since there was a car accident, the roads are crowded.
Yuki ga takusan futta no de, densha ga okureru sō desu.
Because a lot of snow has fallen, it is said [they say, I hear] the train is going to be late. / Because of all the snow, the train will be late, I hear.
Byōki na no de, ryokō ni iku no wa muri desu.
Since I’m ill, taking a trip is out of the question.
Note: As in this example, da changes to na before no de.