The word guy is said to originate with the historical figure of Guy Fawkes whose failed attempt to blow up the Houses of Parliament in London on November 5th, 1606 (known as the Gunpowder Plot), and subsequent execution are celebrated across the UK. Tonight is Guy Fawkes Night (also known as Bonfire Night or Fireworks Night 
). You can read more about its history and traditions here if you like.
Londoners were encouraged to celebrate the foiling of the Gunpowder Plot by lighting large bonfires 
. Children would (and still do) make a âguyâ - an effigy of Guy Fawkes - out of old clothes stuffed with straw, to be set on top of the bonfire and burned. In the 18th century the word guy became a pejorative (a word expressing contempt) used against men wearing shabby clothes. Over many years the wordâs meaning shifted to simply mean âmanâ, and in recent times to refer to a group of people of any sex: âHey guys, howâs it going?â
The Gunpowder Plot takes its name from the vast quantities of gunpowder hidden in the cellars beneath Parliament (36 barrels to be precise ). The word gun 
has an etymology that leads us deep into the history of English, back through its Germanic roots 
and further.
Mentioned in a 1330 Windsor Castle 
catalogue of weapons is: â Una magna balista de cornu quĂŚ vocatur Domina Gunildaâ, meaning âa large cannon from Cornwall called Lady Gunildaâ. But who on earth is Lady Gunilda? Her name is a compound of two Old Norse words gunnr and hildr , which had similar meanings of âbattle, strike, killâ (which is fitting for a cannon, I guess). The first half gunnr is the root of the English word bane which is used in the idiom âbane of my existenceâ . Imagine you have a computer which is always crashing. You might complain loudly that âThis piece of crap is the bane of my existence!â One can understand how bane came to mean something terrible when one sees that an archaic meaning of the word was âsomething poisonous which causes death.â 
Gunnr also seems to be the origin of the German word bahn as in âAutobahnâ - the German highway system . This seems like a stretch, but if the name of a 16th century catholic revolutionary can become a word for âpersonâ, then why canât a word meaning âto strikeâ become âroadâ? It started with a version of the word meaning âto clearâ as in âto clear a forestâ (to clear a forest you must cut down trees by striking them with an axe) 
. Once you clear some forest you have a clearing . Perhaps this clearing runs in a straight line and forms a path through the forest. And perhaps years later after the invention of the car you decide to turn this path into a road , and finally into a highway .
As our world changed so did our words. Do you know of any words that originally meant something very different to what they do now?