Happening or operating at the same time.

Things that are concurrent usually not only happen at the same time but also are similar to each other. So, for example, multitasking computers are capable of performing concurrent tasks. When we take more than one medication at a time, we run the risks involved with concurrent drug use. And at any multiplex theater several movies are running *concurrently*.

Hastily and often carelessly done.

Unlike the other words in this section, *cursory* always implies speed. But it also stresses a lack of attention to detail. Cursory observations are generally shallow or superficial because of their speed. And when citizens complain about a cursory police investigation of a crime, they're distressed by its lack of thoroughness, not its speed.

Passing from one topic to another.

The Latin verb *discurrere* meant “to run about,” and from this word we get our word *discursive,* which often means rambling about over a wide range of topics. A discursive writing style generally isn't encouraged by writing teachers. But some of the great 19th-century writers, such as Charles Lamb and Thomas de Quincey, show that the discursive essay, especially when gracefully written and somewhat personal in tone, can be a pleasure to read. And the man often called the inventor of the essay, the great Michel de Montaigne, might touch on dozens of different topics in the course of a long discursive essay.

One that goes before and indicates the coming of another.

With its prefix *pre-*, meaning “before,” a precursor is literally a “forerunner,” and in fact *forerunner* first appeared as the translation of the Latin *praecursor*. But the two words function a little differently today. A forerunner may simply come before another thing, but a precursor generally paves the way for something. So, for example, the Office of Strategic Services in World War II was the immediate precursor of today's Central Intelligence Agency, while the blues music of the 1930s and 1940s was only one of the precursors of the rock and roll of today.

An animal having four feet.

The quadrupeds include almost all the mammals. (Among the exceptions are whales, bats, and humans.) The Greek equivalent of this Latin word is *tetrapod*. However, the two are not identical, since the tetrapod classification includes *bipeds* such as birds, in which two of the limbs are no longer used for walking. Insects all have six legs, of course, and in the sea there are eight- legged *octopods* (including the octopus). But there are no animals of any kind with an odd number of legs.

The line of ancestors of a person or animal.

What does someone's ancestry have to do with feet? Because someone once thought that a family tree, or genealogical chart, resembled a crane's foot (in French, *pied de grue*), even though cranes' feet only have four talons or claws, no more than any other bird, while a family tree may have hundreds of branches. The word *pedigree* is usually used for purebred animals—cats, racehorses, and dogs, as well as livestock such as cows and sheep. Some people continue to believe that “purity” in human family trees is a good thing as well, though most of us find the idea a little creepy.

Something that interferes with movement or progress.

*Impediment* comes from a Latin verb that meant “to interfere with” or “to get in the way of progress,” as if by tripping up the feet of someone walking. In English, *impediment* still suggests an obstruction or obstacle along a path; for example, a lack of adequate roads and bridges would be called an impediment to economic development. Impediments usually get in the way of something we want. So we may speak of an impediment to communication, marriage, or progress—but something that slows the progress of aging, disease, or decay is rarely called an impediment.

Commonplace, ordinary, or unimaginative.

Most of us know *pedestrian* as a noun meaning someone who travels on foot. But the adjective sense of *pedestrian* as defined here is actually its original meaning. To be pedestrian was to be drab or dull, as if plodding along on foot rather than speeding on horseback or by coach. *Pedestrian* is often used to describe a colorless or lifeless writing style, but it can also describe politicians, public tastes, personal qualities, or possessions. In comparison with the elaborate stage shows put on by today's rock artists, for instance, most of the stage presentations of 1960s rock stars seem pedestrian.