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.
Eboracum
The name "Eboracum" comes from the Common Brittonic "Eburākon", which means "yew tree place". The word for "yew" was "*ebura" in Proto-Celtic (cf. Old Irish "ibar" "yew-tree", (older "iobhar"), , "alder buckthorn", "alder buckthorn"), combined with the proprietive suffix "*-āko(n)" "having" (cf. Welsh "-og", Gaelic "-ach") meaning "yew tree place" (cf. "efrog" in Welsh, "eabhrach/iubhrach" in Irish Gaelic and "eabhrach/iobhrach" in Scottish Gaelic, by which names the city is known in those languages). The name was then Latinized by replacing the Celtic neuter nominative ending "-on" by its Latin equivalent "-um",a common use noted also in Gaul and Lusitania. Various place names, such as Évry, Ivry, Ivrey, Ivory and Ivrac in France would all come from "*eburacon / *eburiacon"; for example: Ivry-la-Bataille (Eure, "Ebriaco" in 1023–1033), Ivry-le-Temple ("Evriacum" in 1199) Évry (Essonne, "Everiaco" in 1158), etc.