Main Entry: ang·strom

Pronunciation: \ˈaŋ-strəm also ˈȯŋ-\

Function: noun

: a unit of length equal to one ten-billionth of a meter

Ångström, Anders Jonas (1814–1874), Swedish astronomer and physicist. One of the early formulators of the science of modern spectroscopy, Ångström wrote extensively on terrestrial magnetism, the conduction of heat, and especially spectroscopy. He published a monumental map of the normal solar spectrum that expressed the length of light waves in units of one ten-millionth of a millimeter, a unit of length now known as the angstrom. He discovered that hydrogen is present in the sun's atmosphere, and he was the first to examine the spectrum of the aurora borealis.