Prefixes Transform Words

Prefixes change a word’s meaning. Let’s look at different categories of prefixes. Some prefixes change a word to mean its opposite. Others change a word to indicate repetition. Still others refer to quantity or position in time, movement, size or are related to science or medicine in some way.

Opposites

One of the first prefixes I learned was un. It is probably the simplest way to change a word to its polar opposite. Comfortable becomes uncomfortable, believable becomes unbelievable. In fact, people will understand your meaning even when you use it to create words that don’t exist. I’m thinking of the words undead and uncool.

Another common prefix for the opposite of is non. It is usually tacked onto adjectives or nouns to convey the opposite of. Examples of adjectives that are changed by the prefix non are: competitive, infectious and perishable. Nouns that are changed by adding non are: resident, believer, and smoker.

The prefixes in and im can also mean the opposite of. Some examples are imperfect and incapable. How do you know which one to use? Root words beginning with an m or p will use the prefix im as in impossible, immeasurable, immobile, and improper. All others will use the prefix in.

Repetition and More

I think the second prefix I learned in school was re. We made lists and lists of re words. It’s a safe bet that if you add re to the beginning of a word, it indicates repetition. Reactivate, rebroadcast, reconfirm all show that you are doing it for a second time.

Other prefixes in this category are extra, super, micro, and macro. Something that is extraordinary is more than ordinary. A supersized order is bigger than a normal order. A microscope is used to look at really tiny things like bacteria. The prefix micro means very small. The opposite is macro and is used primarily in the sciences. For instance, in college I took macroeconomics, an overview of how economics works on a large scale.

Number and Quantity

If you’ve studied geometric shapes you already know loads of prefixes in this category. Can you identify the prefixes in hexagon, octagon, and dodecagon? Those are all polygons—shapes with many sides. The prefix specifies how many sides. Do you know any triplets or quintuplets? Me neither, but a simple prefix lets me know if the siblings are a set of three or five. Perhaps cycling is your thing. Unicycles, bicycles, and tricycles each have a different number of wheels. Recognizing these prefixes allows you to understand other words.

Time Related Prefixes

When a teacher begins a unit, he or she often gives students a pretest to gauge their knowledge on a subject. Then after instruction students take a posttest which measures what they learned. In this example pre means before and post means after. Other time related prefixes are ex as in expresident, and fore as in a book’s foreword.

Movement and Distance

Transportation, transfer, and transcontinental all begin with the prefix trans. Can you guess what it means? It has to do with movement. Transportation moves people and goods from one place to another. You might transfer money from one account to another. In 1869 the transcontinental railroad made travel from one coast of the North American continent to the other, possibly changing history forever.

Another prefix related to distance is tele. Telegraph, telephone, and telescope are ways to shrink distance. Before cell phones and fax machines, telegraphs were the fastest way to send a written message. The prefix tele means distance and the root word graph means writing. A telegraph could span the country in minutes but it took 12 days for the pony express to deliver a message from San Francisco to New York in 1861. Check out this website to participate in or follow the annual Pony Express re-ride.

Finally, medicine and science have their own specialized prefixes which I won’t go into here. Being able to tack on prefixes automatically expands your vocabulary.