It's official. "Ginormous," an adjective that combines the words gigantic and enormous, has received the stamp of approval from Merriam-Webster and is now to be included in the company's latest collegiate dictionary. And while linguistic purists may scoff at the notion of such a word being included in the prestigious tome, investors can glean some insights from both the word's introduction and its meaning.

Ginormous opportunities require patience
On its face, the word "ginormous" might appear to be an overnight success story, owing its success to its use by Will Ferrell in the 2003 hit Elf, but that's not entirely the case. According to the fine folks at Merriam-Webster, the word can actually trace its origins back to the year 1948, when it appeared in a British dictionary of military slang.

I mention this because a number of so-called sexy investment themes may at first appear to be new and, thus, are easily dismissed by investors who think they're nothing more than a fad that will fade away with relative alacrity. A closer look, however, may reveal that just as the word ginormous took more than a half century to move from the fringe to the mainstream, certain investment themes also have long-standing pedigrees.

Take, for instance, nanotechnology. The field has generated some buzz since 2002, but the actual idea of nanotechnology -- manipulating atoms and molecules to design new products -- was first conceived in 1959 by the famed physicist and Nobel Prize winner, Richard Feynman. But it wasn't until 1989 that two IBM (NYSE:IBM) researchers first manipulated individual atoms.

Since that time, the amount of progress in the field has been nothing short of phenomenal, and in just the past few months, both IBM and Hewlett-Packard (NYSE:HPQ) have commercialized legitimate nanotechnology products. Moreover, billionaire investor Wilbur Ross, who owns Nano-Tex, has publicly stated that he believes nanotechnology-enhanced textiles will be the basis of a $120 billion industry by 2012 -- up from $11 billion today.

According to Lux research, the amount of all products enabled by nanotechnology could reach $2.6 trillion by 2015. One way for investors to play the field is to consider an investment in Motley Fool Rule Breakers recommendation Harris & Harris (NASDAQ:TINY), which owns an equity stake in more than two-dozen privately owned nanotechnology start-up companies.

Ginormity knows no bounds
In addition to the $2.6 trillion nanotechnology market, there are still other ginormous opportunities. For example, according to uber-venture capitalist John Doerr, cleantech -- investments in renewable energies -- has the potential to be the "largest economic opportunity of the century."

A quick purview of the investment horizon reveals that this, too, may be more than just a bit of speculative investment hyperbole. Consider, for example, that BP has recently made a sizeable investment in Synthetic Genomics, a leader in the emerging field of synthetic biology. The investment was undertaken in the belief that its technology to create "designer bacteria" (essentially, new artificial life forms) could transform the oil and gas industry by finding newer and more efficient methods of producing everything from ethanol and biodiesel to hydrogen. If the company fails, BP has still hedged its cleantech bet by investing $500 million at the University of California at Berkeley in biofuel research and development.

This past week also saw the solar industry provide further evidence of its growing power when First Solar (NASDAQ:FSLR) announced it would be supplying 658 megawatts in new orders between now and 2012, and Trina Solar signed a contract with a German company to supply another 100MW of solar modules. The deals offer some confirmation to Clean Edge Research's estimate that the solar industry will grow from the $15 billion industry that it is today to a $70 billion industry by 2016.

Another cleantech-related field that could experience some healthy growth is the entire bioplastics industry. You may recall that earlier this spring, Archer Daniels Midland (NYSE:ADM) teamed up with Metabolix to produce 110 million pounds of biodegradable plastic starting in 2008. This is just a drop in the proverbial plastic bucket, but even if just a few percentage points of the 350 billion pound plastic business can be converted to plastics made with corn starch, the opportunity could be, well, ginormous.

The robotics field is ripe for growth
But the ginormous opportunities don't stop there. A number of other fields, such as RNAi, RFID, and rapid prototype manufacturing, also appear ripe for ginormous growth in the years ahead. My personal favorite is robotics. I have written frequently about how Intuitive Surgical's da Vinci robotic system is now being used to perform nearly half of all prostatectomies. This figure is up from just a few percentage points just five years ago. More exciting still is how such robotic surgical equipment might soon find a home performing hysterectomies and even heart surgeries.

The entire field of robotics is expected to become a $50 billion industry by 2015, and according to Bill Gates, we are just now at "the dawn of the robotics age." To this end, Microsoft (NASDAQ:MSFT) now has a sizeable robotic initiative, and hardly a day goes by without some new robotic advanced being announced.

Just last week, iRobot and TASER International (NASDAQ:TASR) announced they were teaming up to create a robot that could incorporate TASER's stun guns. Then further consider that the U.S. Army has indicated that by 2015, it expects one-third of our fighting force to consist of robots, and the opportunity in robotics speaks for itself.

Foolish final word
In his best-selling and classic book, The Intelligent Investor, Benjamin Graham wrote, "It has long been the prevalent view that the art of successful investment lies first in the choice of those industries that are most likely to grow in the future and then in identifying the most promising companies in those industries."

So far so good, right? Not so fast. Graham, who wrote his book in 1949, also offered an important caveat, and he used the airline industry to make his point. He noted that "air-transport stocks" generated a good deal of excitement in the early 1940s and were the subject of the hottest mutual funds of the era. Unfortunately, like the stocks these funds owned, they turned out to be an investing disaster. And as Jason Zweig noted in his latest update of Graham's book, it is commonly accepted today that the cumulative earnings of the airline industry over its entire history have been negative.

Now, my point is not that any of the aforementioned fields will also be net losers. Rather, it is that history constantly reminds investors not to get overly confident just because a company is involved in some promising, fast-growing field like nanotechnology, cleantech, or robotics.

Investors still need to do their due diligence and understand the nuts and bolts of the company, its technology, and its competitive landscape. If they don't, they could find their investment portfolio subject to a serious "smackdown" -- yet another new word added to this year's Merriam Webster.

Curious about other ginormous investment opportunities? Check out these articles:

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Harris & Harris, Intuitive Surgical, TASER, and iRobot are all Rule Breakers recommendations. Microsoft is an Inside Value pick.

Fool contributor Jack Uldrich's own investment portfolio has not yet reached ginormous status, but it is definitely growing. He owns stock in Harris & Harris, IBM, Intuitive Surgical, and iRobot. The Fool has a strict disclosure policy.