Ok, ok, enough already! You go about indiscriminately using terms like Squid, Nerd, Geek, without regard to their formal definition, as used in the land of Mudd. Well, here goes:
NERD: Nerd has a few definitions. First, it is an overriding category. Anyone that is a squid, squeif, geek, etc. is necessarily a nerd- although one can be a nerd without being any of the others. Second, a nerd is anyone who does anything scientific or technical, or is a little "different" socially (e.g. is known to catch Fruit Loops, tossed in the air, in the mouth, at dinner), or is reasonably involved in anything out of the ordinary. Thus the existence of such terms as "Flute Nerd" (as this author has been known to term his mother). Many people fit the general term Nerd, although sometimes a modifier is needed: "Physics Nerd," "Music Nerd," "Comedy Nerd," and so on. Finally, the descriptive term nerd, when not as defined above, is one of those concepts that is very hard to define- it is sort of an approach to life; often you can think about someone you know, and realize that they are a nerd, without first going through a checklist of "nerd" qualities.
SQUID: Perhaps the most popular and most overused nerdology term at Harvey Mudd, a squid is NOT anyone who displays nerdy qualities. That is, in the third definition above, a "nerd." A squid, if one is to be a purist about it, is one who spends all of their time cooped up in their room studying. One generally never sees squids, except in class. (This is of course the extreme case- one can have elements of squidliness in them without being a full blown extreme squid in all of its glory). A squid, when presented with the unfortunate situation of having all of his (or her) work done, will not go and blow off time by hanging out with other people, in the lounge, playing frisbee, etc. A true squid during his free time will do something useful: read a book, get ahead on homework, start that Retch research paper that is due in a measly six weeks- but never do much in the way of social interaction.
SQUEIF: This form of nerd is very often confused with a squid. A squeif is one who does very well in academics. The person who always scores above average on tests, who has high scored multiple tests, who has a GPA above ~3.5, is a squeif. Note the distinction between squeif and squid. One can be a squid, and still be a C+ student; just because you study all the time does not mean that you will high score everything. Note that often squeifism and squidism are correlated. To be a squeif, one must often necessarily be a squid; and, if one is a squid, one will often also be a squeif. But they are nonetheless separate and distinct qualities.
SCHNOID: The term "schnoid" implies computer use. A "Computer Nerd" is a schnoid. Note that this computer use must be nerdy in order to constitute schnoidism. Thus, one who stays up late at night playing Moria is not necessarily a schnoid, while one who tweaks around with the source code and programs Moria is. Someone who has to find eigenvaules on the computer for pChem is not a schnoid, but someone who is not in the class but tries to find those eigenvalues as a way of blowing off time most definitely is a schnoid.
CJ: (That's "Computer Jock" for the uninitiated). A CJ is a schnoid who knows what he is doing. A schnoid very good at being a schnoid is a CJ. Now, this term is not terribly well defined. The common question is, how much of a schnoid must one be to be a CJ? Well, in general, one can only be considered a CJ if the stuff one does is computer science specific. So, if you are an extreme "Physics Schnoid," you can program Pascal inside and out, you can write simulations of physical systems in no time flat, and spend lots of time on the computer, you aren't really a CJ. If, however, you go around configuring system disks, rebooting the Vax, rewriting terminal server software, or improving the operating system of any computer, you are very likely a CJ.
GEEK: A geek is more of a social than an academic term. A person can be a geek regardless of whether they are majoring in English or Math, regardless of whether they are a straight-A student or a repeated ITR. A geek is the sort of person who hangs around and just acts, or seems, terribly nerdy (or really, geeky). They often have relatively loud voices, and lack certain social skills. They are the sort of person that, when others are confronted with the possibility of their presence, roll their eyes and try to find a way to go somewhere else. Often the worse quality in a geek is the geek's complete inability to recognize that they may in some way be a geek. The worst sort of geek really thinks he's a great guy that other people want to be with.
DWEEB: A dweeb is a person who is really clueless in a nerdy sort of way. Again, you can be a dweeb regardless of academic performance. Dweebs are the sort of people who hang around, don't say a whole lot, and rarely have very loud voices. Another characteristic is a dumb laugh (yuk yuk yuk). Every now and then they will make some sort of clueless comment that is either an attempt at being funny by repeating, perhaps with a paraphrase, a joke (and not a very good one) that someone had said quite recently, or a comment that indicates they have more or less missed the point of what was being said. Dweebs are not stupid, just a little socially clueless- and are generally inoffensive creatures.
DORK: A dork is a combination of a dweeb and a geek- a loud and offensive dweeb, really. They are clueless, but don't realize it, and tend to aggressively enforce their cluelessness on others. If someone has made a joke, a dork will repeat, or make a hopelessly failed attempt to expound on, the joke, in a loud voice, and then look around at everyone with a really stupid smile on their face, not realizing that what they said was dumb and not in the slightest bit funny. This sort of thing can happen quite frequently. Dorks are not as offensive to be around as geeks, but are more offensive to be around than dweebs.
SQUARE: It is unclear whether this term really fits within the domain of nerdology, but it is often used in that context, so the definition will be given here. A square is someone who is somehow old fashioned or even prudish in non-nanny sort of way. Telltale square characteristics include listening to mainly classical music, refusing to get drunk or even to drink, or an acute sense of morals, regarding, ahem, male/female realtionships, among other things. Some squares tend to attempt to enforce their squareness on others ("you must not drink," or "all rock music is inspired by the devil.") These squares can be hard to deal with if you are not a square yourself, who sees eye to eye with the vociferous square. Other squares can be quite reticeint about their squareness, often enough that unless you know them pretty well, you wouldn't know about their square qualities.
So there you have it. Next time, be careful before you call your roommate a squid because he spent the whole night doing nerdy things on his Amiga- the proper term would be "schnoid" in that case. And so on.
Note that all of these, as was stated in the definition of "squid," are extreme cases. There are indeed individuals who fit the extreme definitions, but more common are people who are on the whole normal but display (occasionally) some qualities of various forms of nerdism (i.e. squidism, schnoidism, squeifism, CJism, geekism, dweebism, dorkism, and squareism).