niebla
ES [ˈnjeβla] ~ DE Nebel · both “fog, mist”
If you’ve ever travelled on Austrian or German highways, you must have surely noticed the big road signs with Bei Nebel text on them. The sign says “During a fog”, and instructs the drivers to use fog lights during fogs. What a surprise it was when I found out in a videogame, that the word for fog in Spanish is very similar to this one - La Niebla. This is no accident, and it is an awesome bridge between languages. Digging deeper, there is even a connection with Czech nebe, which honestly did not even cross my mind that it would be possible.
A rare three-family handshake. Spanish niebla (from Latin nebula), German Nebel (from Proto-Germanic *nebulaz) and Czech nebe all trace back to the same Proto-Indo-European root *nebh-, “cloud, mist.” Romance and Germanic kept it on the ground as fog; Slavic let it rise - Czech nebe means the sky, and by extension heaven. English took the Latin form almost untouched: a nebula is a cloud in space, and nebulous means hazy. So the fog you can't see through in Madrid, the Nebel over the Rhine and the Czech heavens are, underneath, the same ancient word for cloud.