To form most words in English, you add affixes to roots. Prefixes, the subject of this section, are affixed, or added, to the beginning of words, before the roots. For example, the word prescribe is formed by adding the prefix pre- to the root scribe. To prescribe means “to write something before.” The doctor writes down—some might say scribbles—the name of the medicine before the pharmacist fills the prescription.

The meanings of prefixes are relatively consistent. If you know that mis- consistently means “bad,” then you can make educated guesses about the meanings of a number of unknown words that contain mis-. You can figure out that a mishap is similar to a mistake. You can guess that if an engine misfires because of a bad cylinder, someone may have mishandled the repairs. If you misread directions, you might be misled down the wrong road. Knowing the meaning of this prefix doesn’t guarantee you’ll understand every mis- word, but it does give you a sense when you come across a word with that prefix, that it’s probably negative. Knowing the meaning of a prefix is a good start in decoding the meaning of a word.

Test that same theory on words that start with the prefix fore-, which means “before.” Make some educated guesses or inferences about these words that begin with fore-. Record your answers using your notes. When you are finished, check your understanding to see sample responses.

1. Is your pet’s forepaw his front leg or a back leg?
2. Are forelocks more like bangs or ponytails?
3. Is your forefather a lot older or a lot younger than you?
4. Is your forearm closer to your wrist or your shoulder?
5. Is a weather forecaster’s job to let you know how muggy it was last week or how rainy it will be tomorrow?

If you’ve been “fixin to” improve your vocabulary by learning more prefixes, this rap should motivate you. Click below to watch “Prefixes Rap.”

A few prefixes retain their meaning but differ in their written form. For instance, the prefix in- meaning “in or not” changes to il- before roots beginning with l, as in the word illogical, and to im- before roots beginning with m, b, and p, as in immobile, imbalance, important. These prefixes change spelling primarily because the words sound better and are easier to say. For example, Illegal is easier to say than inlegal.

After you have had a chance to review the prefixes, test how well you have retained their meaning. Drag and drop each prefix below next to its meaning.