1. Indicates a cause or reason: "in that, since, because."
NOTE: No de and kara differ in two ways: first, no de usually indicates a more objective cause or reason, kara is a more subjective one; thus kara is often used with 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, they say 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.
Hope this helps!
°˖ ✧◝(○ ヮ ○)◜✧˖ ° こゆうきあいはら °˖ ✧◝(○ ヮ ○)◜✧˖ °