Geek: Originally the term referred to a carnival performer who would bite the head of animals, most commonly a chicken. It comes from “geck”, an old British term for “fool” which stems from a German word of the same spelling; another derivative is the Dutch “gek” (a crazy person). The most likely explanation for its modern usage comes from the idea that somebody who bit off animal heads in a carnival probably wasn’t at the center of mainstream society.
(I must add that I particularly like the New Hacker’s Dictionary comment that geeks are “people who did not go to their high school proms, and many would be offended by the suggestion that they should have even wanted to.”)
Mouse: The term was first used in print in 1965 and stems from the Stanford Research Institute. The likely origin is that early models had the cord running from the back rather than the front, in a similar position to a rodent’s tail. It seems it took some time for this to be accepted as the standard term, with a 1970 patent using the less memorable “X-Y Position Indicator for a Display System”.
Spam: It appears that originally the term didn’t refer to e-mail messages specifically, but rather unwanted electronic communication in general. The exact date isn’t confirmed, but at some point in the late 1980s, less sociable members of Multi-User Dungeons (MUD) (imagine a text-only version of Second Life) would repeatedly type the word SPAM to make sure other users’ comments disappeared from the screen.
Of course, the reason that word was chosen is almost certainly a result of this 1970 sketch from Monty Python’s Flying Circus:
Blog: The term web log appears to have been coined by Jorn Barger of the Robot Wisdom site in 1997 to refer to a list of links. The contracted form appears to have been created by Peter Merholz of peterme.com two years later, as shown midway down the left-hand column on this archived page.
An important linguistic note to remember is that if you ever want to *really* annoy a blogger, refer to an individual post as “a blog”.
Computer bug: this is one where the most-cited explanation is a myth. In 1946, Grace Hopper, who later created the COBOL programming language, is said to have come up with the term ‘bug’ after a moth became trapped in an in-development computer and caused problems. In fact the term was already well-established and even referred to in the project log-book:
When and how the term actually originated isn’t clear, but Thomas Edison referred to “Bugs” being a known term for hardware problems in an 1878 letter. Excerpt:
It has been just so in all of my inventions. The first step is an intuition, and comes with a burst, then difficulties arise — this thing gives out and [it is] then that ‘Bugs’ — as such little faults and difficulties are called — show themselves and months of intense watching, study and labor are requisite before commercial success or failure is certainly reached.