An organism (such as a bacterium) of microscopic or less than microscopic size.

A hint of the Greek word *bios*, meaning “life,” can be seen in *microbe*. Microbes, or *microorganisms*, include bacteria, protozoa, fungi, algae, amoebas, and slime molds. Many people think of microbes as simply the causes of disease, but every human is actually the host to billions of microbes, and most of them are essential to our life. Much research is now going into possible *microbial* sources of future energy; algae looks particularly promising, as do certain newly discovered or created microbes that can produce cellulose, to be turned into ethanol and other biofuels.

A scientist who studies extremely small forms of life, such as bacteria and viruses.

Since microorganisms are involved in almost every aspect of life on earth, microbiologists work across a broad range of subject areas. Some study only viruses, some only bacteria. A marine microbiologist studies the roles of microbial communities in the sea. A soil microbiologist might focus on the use and spread of nitrogen. Veterinary microbiologists might research bacteria that attack racehorses or diagnose anthrax in cows. And the government puts microbiologists to work studying whether microbes could adapt to life on the surface of Mars, and how to defend ourselves against the possibility of germ warfare.

A beer made by a brewery that makes beer in small amounts.

Microbrews are usually beers or ales made with special malts and hops, unfiltered and unpasteurized, and thus distinctive in their aroma and flavor. Many microbreweries double as bar/restaurants, called *brewpubs*, where the gleaming vats may be visible behind a glass partition. “Craft brewing” and the opening of local brewpubs began in earnest in the U.S. in the 1980s. But not everyone is willing to pay extra for a beer, and lots of people are simply used to the blander taste of the best-selling beers, so by 2008 microbrews still only accounted for about 4% of all beer sold in the U.S.

The essentially uniform local climate of a small site or habitat.

The microclimate of an industrial park may be quite different from that of a nearby wooded park, since the plants absorb light and heat while asphalt parking lots and rooftops radiate them back into the air. A microclimate can offer a small growing area for crops that wouldn't do well in the wider region, so skilled gardeners take advantage of microclimates by carefully choosing and positioning their plants. San Francisco's hills, oceanfront, and bay shore, along with its alternating areas of concrete and greenery, make it a city of microclimates.

Consisting of many cells.

Multicellular organisms are distinguished from the very primitive single- celled organisms—bacteria, algae, amoebas, etc. Even sponges, simple as they are, have specialized cell types such as digestive cells. In complex multicellular organisms, only the surface cells can exchange substances with the external environment, so the organisms have developed transport systems such as the circulatory system, in which the blood brings gases and nutrients to the cells and removes waste products from them.

Involving two or more subject areas.

A *discipline* is a field of study. So a multidisciplinary (or *interdisciplinary*) course is a team-taught course in which students are asked to understand a single subject as it's seen by two or more traditional disciplines. Multidisciplinary teaching can open students' eyes to different views of a subject that they had never considered before. A multidisciplinary panel discussion, on the other hand, presents views from scholars in different fields but may leave any merging of the information to the audience.

Having or occurring in great variety; diverse.

*Multifarious* is a rather grand word, probably not for everyday use, but when you want to emphasize great variety—such as the huge number of uses to which a state-of-the-art cell phone can be put—it can be effective. Dictionary fans are constantly amazed by the multifarious meanings of the word *set* (47 of them in one unabridged dictionary), and thesaurus lovers may marvel at the multifarious synonyms for *drunk*.

Involving more than two nations or parties.

Since *lateral* means “side” (see LATER), *multilateral* means basically “many-sided.” The philosophy of *multilateralism* claims that the best solutions generally result when as many of the world's nations as possible are involved in discussions, and *multilateralists* often favor strengthening the United Nations. Today multilateralism can be seen at work in, for example, the World Health Organization, the World Trade Organization, and the International Criminal Court. But the U.S. doesn't always join the major multilateral organizations, instead often behaving as if a *unilateral* approach —that is, going it alone—was best for the interests of a powerful nation.