Eureka (word)
The exclamation 'Eureka!' is attributed to the ancient Greek scholar Archimedes. He reportedly proclaimed "Eureka! Eureka!" after he had stepped into a bath and noticed that the water level rose, whereupon he suddenly understood that the volume of water displaced must be equal to the volume of the part of his body he had submerged. (This relation is "not" what is known as Archimedes' principle—that deals with the "upthrust" experienced by a body immersed in a fluid.) He then realized that the volume of irregular objects could be measured with precision, a previously intractable problem. He is said to have been so eager to share his discovery that he leapt out of his bathtub and ran naked through the streets of Syracuse.
Urtica dioica
In the German language, the idiom "sich in die Nesseln setzen", or to sit in nettles, means to get into trouble.
In Hungarian, the idiom "csalánba nem üt a mennykő" (no lightning strikes the nettle) means bad things never happen to bad people. The same idiom exists in the Serbian language неће гром у коприве. In Dutch, a "netelige situatie" means a predicament. In French, the idiom "faut pas pousser mémé dans les orties" (don't push grandma in the nettles) means that we should be careful not to abuse a situation. The name urticaria for hives comes from the Latin name of nettle ("Urtica", from urere, to burn).