Thunder in Chinese / Japanese...

雷 can mean thunder, lightning, thunderbolt, mine (weapon), or slang for something terrifying or a fit of anger.

Some will say it is the symbol of the god of thunder or the god of lightning.

雷 is also a Chinese surname that romanizes as Lei.

雷神 is how to write the Japanese “Thunder God.” They don't really have separate words for thunder and lightning in Japanese, so this is also the “Lightning God.”

雷神 makes sense in Chinese (though not a common title).

This is also the origin of the English name Raiden.

突貫 is a Japanese word that can be translated as lightning attack, charge, or rush.

It's about a fast run or attack at the speed of lightning.

閃電 is the title for lightning in Chinese.

The first character means flash, dodge, or get out of the way. In this case, it's the “flash” meaning. Sometimes this character can be used to mean lightning by itself.

The second character means electricity.

See Also:  Thunder | Rain | Storm

電 is the title for electricity in Chinese, Japanese Kanji, and old Korean Hanja.

While this character means electric or electricity, it can also be used to mean lightning.

Note: This Kanji is not usually used alone like this in Japanese.

See Also:  Thunder | Power | Energy | Rain

電氣 is the title for electricity in Japanese Kanji.

This can also be used to mean lightning in Japanese.

See Also:  Thunder | Power | Energy | Rain

白天不做亏心事夜半敲门不吃惊 literally translates as: [If one does] not do bad things in the daytime, one need not be alarmed at knocks on the door in the middle of the night.

The meaning is something like, “A quiet conscience sleeps in thunder.” Basically, the message is, “don't commit crimes and you won't be jumpy every time the doorbell rings (so don't do anything wrong and your life will have fewer worries and you can sleep at night).”