Do my sons know me or what? I was actually reading up on Anglo-Saxon language during the power outage. Leorning-cnihtas is the Old English construction for "disciples." Literally, it is "Knights of learning." It seems to be present in several dialects, suggesting that the phrase was in general use, and thus earlier than our first recording of it. Poetic constructions like this were called kennings, and the example usually given is "whale-road" for sea. Which by clang association always brought to my mind someone's-in-the-kitchen-with-Dinah...
My first task when I got back online, however, was to research Wind Chill. With the power out going into the coldest two nights of the year, heat loss, and what accelerates it, was much on my mind. Wind chill is a concept measuring the heat loss of human beings in cold and wind. Objects don't get any colder once they reach the outside temperature, no matter how much wind there is. But human beings need to maintain their 100F. Whole different matter. Other objects lose heat more rapidly in wind as well, though not at the same rate. There is a nifty explanation here, more detailed than the usual wind-chill chart, but still brief. I hadn't thought of the solar radiation part.
It will be zero degrees with wind, wind-chill to minus 20 tonight. My personal definitions set WC 20 above as cold, zero as Cold, and minus 20 as Damn Cold. Minus 28 with a little wind, and minus 11 with a stiff wind are the worst I've experienced. Apparently it's supposed to feel slightly colder in places like this because of the increased moisture in the air, but I can't speak to that myself.
For those of you disappointed not to find any actual Indo-European roots here, I will dredge up an interesting one from memory.
*ghosti refers to the interactive relationships between strangers. From it we get our words ghost, guest, hostile, hostel, and host (in several senses). Meeting a stranger was fraught with peril. Is he an enemy? A trader? The acceptance of hospitality created a mutual obligation that was protective for both parties. Gift-giving created similar obligations. To accept a gift was to imply that you would shortly give one in return. Native Americans practiced a similar obligation of exchange, and when they gave a gift expected one in return as a sign of unity and peace. When Europeans were not forthcoming with a reciprocal gift, the Native American would demand his gift back. Thus the term Indian Giver, resulting from that misunderstanding.
This contractual binding undergirds much of informal legal custom, and became a foundation for our legal systems. The words "legal" and "ligament" derive from the same root.