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.
Kobza
The term kobza is of Turkic origin and is related to the terms kobyz and komuz, thought to have been introduced into the Ukrainian language in the 13th century with the migration of a sizable group of Turkic people from Abkhazia settling in the Poltava region. It was usually played by a bard or minstrel known as a "kobzar" (occasionally in earlier times a "kobeznik"), who accompanies his recitation of epic poetry called "duma" in Ukrainian.