Word To Use Today: conk.

 A conk is a nose, and has been since the early 1800s.

It's probably so-called after the sea shell called a conch:

conch shell. Photo by cheesy42

There's not that much resemblance, I know, but the shells are used as trumpets, which might be a clue to how the word got attached to the nose.

Conk meaning nose is not a word to be used in formal circumstances, and neither is conk meaning to hit someone (probably on the head, and quite possibly on the nose).

Conking out is a similarly informal expression meaning to stop working. This may be a happy thing: if someone conks out on the sofa then they've gone to sleep; but if an engine conks out then that's going to be annoying, especially if the engine in question is keeping a plane in the air (the term was used a lot in this sense in World War I). This meaning of the word conk seems to have originated among pioneer motor-cyclists a few years before WWI, and was probably an imitation of the sound of a stalling engine. 

When the engine starts to "conk conk conk" retard the spark a trifle, or give more throttle if an increase in speed is permissable. Motorcycle Illustrated 1911.

The hairstyle called the conk was worn by men with naturally frizzy hair in the mid twentieth century, and it relied on the chemical congolene as a straightening agent. Congolene was homemade, extremely corrosive, and made of lye (sodium hydroxide made from wood ash) mixed quite often with potatoes and eggs.

A final, again apparently random meaning of conk is that it's the fruiting body of a bracket fungus - that is, the visible bit of a fungus that sticks out of a tree trunk. I can't find any origin for this word - it's not in the OED - so it's probably recent.

It's a vastly satisfying word, anyway. I wonder what it's going to mean next?