Heiligenschein

Recently, I stumbled upon the word heiligenschein. At first, I didn't know what to make of it, but through Wikipedia I learned that a heiligenschein is

"an optical phenomenon which creates a bright spot around the shadow of the viewer's head. It is created when the surface on which the shadow falls has special optical characteristics. Dewy grass is known to exhibit these characteristics, and creates a Heiligenschein. Nearly spherical dew droplets act as lenses to focus the light on the surface beneath them. Some of this light 'backscatters' in the direction of the sunlight as it passes back through the dew droplet. This makes the antisolar point appear the brightest.“

( http://en.wikipedia.org/wiki/Heiligenschein Wikipedia, 7.08.12)

This is an interesting topic, btw! See also these links with nice sample photos of heiligenschein: http://www.atoptics.co.uk/droplets/heilig.htm (link from 7.08.12).

As a German word, heiligenschein means "halo" or "glory", so both the English and the German language have their native word for that notion and, of course, there is no need for English speakers to use the German word, and vice versa, in that sense.

So why did English speakers take to using the word heiligenschein in their language?

A heiligenschein is a particular optical phenomenon that looks similar to a halo.

And because of that similarity someone introduced the German heiligenschein as a metaphorical expression for that newly discovered phenomenon. 

Maybe a German speaking scientist was involved in the coinage, that would explain the choice of the source language (but I do have the impression that in the realm of physics it is not rare that German words are used for denoting particular phenomena).

I won't leave out another interesting feature of heiligenschein: In German, it is a compound word, consisting of the components Heiligen and Schein, and although the word has acquired its own special lexical meaning, the meanings of the components are still transparent: a Heiliger is a saint, and Schein means glow or shine. 

Native speakers of the recipient language English can't make out those constituents any more, so in English, the word has to be regarded as a simplex.

To summarize the previous description:

The coining and usage of the English word heiligenschein exhibits some typical features of loanwords:

Words of one language enter another language conveying new content, new notions, be it scientifc or technological, philosophical or religious vocabulary (there can be other reasons, but that's for another post).

The words often do not retain their original spectrum of meaning, but take on a more specialized meaning in the recipient language. 

If the loanword is a compound in the donor language, it is probable that the speakers of the recipient language don't understand its constituents any more and therefore treat the word as a simplex. 

Btw, in the 2006 Scripps National Spelling Bee, heiligenschein was the word which eliminated a contestant who finished fourth for the second consecutive year. As this competition whas televised live in a primetime broadcast, the event involving heiligenschein got widely known and is credited with increasing the prominence of the spelling bee in American culture.