Made stronger or more capable by electronic or mechanical devices.

The science of *bionics* uses knowledge about how biological systems work to help solve engineering problems. The material Velcro, for example, was inspired by the way burrs behave when they stick to your clothes, and some computer chips are now wired in ways that imitate the “wiring” of the brain and nervous system. But in popular use, the adjective *bionic* almost always describes artificial limbs or other bodily parts that work as much like real ones as possible. A perfect bionic arm would move and function as easily as a real arm—a goal we're rapidly getting closer to.

The removal and examination of tissue, cells, or fluids from a living body.

Matter examined in a biopsy is always taken from a living organism. Most biopsies are done by using a needle to extract tissue or fluid, but some may instead require cutting, and others may amount to nothing more than swabbing the inside of the patient's cheek. Biopsies are best known as a means of detecting cancer, but a doctor may also take a biopsy of heart muscle to investigate suspected heart disease, for example, or perform a biopsy on a pregnant woman to test for disorders in the fetus.

Able to be broken down into harmless substances by microorganisms or other living things.

In *biodegradable,* with its root *grad,* “to step or move,” and its prefix *de-* “downward,” we get an adjective describing things that can be broken down into basic substances through normal environmental processes. Animal and plant products are normally biodegradable, but mineral substances such as metals, glass, and plastics usually are not. Newly developed biodegradable plastics are now appearing in numerous products. However, “biodegradable” products can vary greatly in how long they take to break down. A loaf of bread may require only a couple of weeks, and a piece of paper may vanish in a couple of months, but some “biodegradable” plastic milk cartons may take four or five years.

(1) The close living together of two different forms of life in a way that benefits both. (2) A cooperative relationship between two people or groups.

With its prefix *sym-,* “with,” *symbiosis* expresses the notion of cooperation between living things. *Symbiotic* associations are found throughout the plant and animal world. You may have read, for instance, of the little blackbird plover, which picks the teeth of the fierce African crocodile. Or the bird called the African honeyguide, which leads a little mammal called the ratel to a bees' nest, which the ratel, protected from the bees by its thick fur, then breaks open, and both it and the honeyguide feast on the honey. Or even our own bodies, which are home to millions of bacteria—especially the bacterium *E. coli* in our intestines—and neither we nor *E. coli* could live without the other. You can probably think of plenty of human relationships that could be called symbiotic as well.

Origin, beginning.

The traditional Greek name for the first and best-known book of the Bible is Genesis, meaning “origin.” Genesis tells the stories of the creation, Adam and Eve, Cain and Abel, Noah's ark, the Tower of Babel, Abraham and his sons, and more—the stories that explain how the world and humanity were created, as well as much about how humanity, and especially the descendants of Abraham, relate to the rest of the world. Today we use *genesis* to refer to the creative beginnings of much smaller things, but never unimportant ones.

A machine by which mechanical energy is changed into electrical energy

Generators work by rotating a coil of wire in a magnetic field, causing a current to flow in the wire. A generator may be a huge spinning turbine powered by water, wind, steam, gas, or nuclear reactions, which sends electricity out through power lines to thousands of customers. But normally when we use the word, we're thinking of a small machine powered by gasoline or diesel, such as you might keep in your basement for those times when a storm knocks out your power, to create electricity right in front of your eyes. A special kind of generator called an alternator powers a car's electrical system (including its lights, power steering, etc.) while the car is running.

Kind, sort; especially a distinctive type or category of literature, art, or music.

*Genre*, as you might guess from the way it sounds, comes straight from French, a language based on Latin. It's closely related to *genus*, a word you may have encountered in biology class. Both words contain the *gen-* root because they indicate that everything in a particular category (a genre or a genus) belongs to the same “family” and thus has the same origins. So the main genres of classical music would include symphonies, sonatas, and opera, and the major genres of literature would include novels, short stories, poetry, and drama. But within the category of novels, we could also say that detective novels, sci-fi novels, romance novels, and young-adult novels are separate genres.

Producing or causing cancer.

It sometimes seems as if the list of carcinogenic substances gets longer every day. A substance such as a food additive that's been in common use for years may unexpectedly show signs of being carcinogenic in laboratory experiments. When that happens, the suspected *carcinogen* will often have to be withdrawn from the market. When a building material like asbestos turns out to be a carcinogen, it may also have to be physically removed from buildings. English has hundreds of other scientific words ending in *-genic* (such as *allergenic*), and in almost all of them the ending means “causing.”