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Word Parts

Most medical words derive from Greek or Latin and therefore may look and sound odd to you. However, once you have taken the time to learn the meanings of the word parts, you will be able to understand most of the medical terms you encounter, regardless of how big or complex they appear. There are three types of word parts that you need to know: (1) suffixes, (2) prefixes, and (3) combining forms (created by joining a word root to a combining vowel). You will use these word parts in a three-step process to find the meanings of medical terms. You also need to know the abbreviations and pathology terms that are used in health care; however, the three-step deciphering process often does not work with these terms.


Word Root (WR) +

Combining Vowel (CV) =

Combined Form (CF)


A suffix is a word part that comes at the end of the medical term. If the suffix -meter (instrument used to measure) is added to the combining form therm/o, the result is the creation of the word therm/o/meter, an instrument used to measure heat.


A prefix is a word part that comes at the beginning of the medical term. For example, again consider the word root therm. If it is joined with the prefix hypo- (beneath or below) and the suffix -ia (condition), then a new word is created: hypo/therm/ia, a condition of low heat. As you may already know, this term is used in reference to a condition of low body temperature.

Combining Forms

The combining form is created by joining a word root with a combining vowel. A word root (WR) is the main stem, or primary meaning, of the word. An example using a nonmedical term is the word walking. The main stem or root of this word is walk. A combining vowel (CV) is used to make the medical term easier to pronounce. You could say that it makes medical terms more user-friendly for the tongue. A combining vowel is not always necessary. When it is needed, in nearly all cases the combining vowel is an o, although there are a few exceptions.

The combining vowel has no impact on the meaning of the term; it is placed between word parts to link them together. For example, consider the root therm, which means heat. If this word root is combined with the combining vowel o, the result is the combining form therm/o. Combining vowels are typically used to link word parts together regardless of whether the following part is a suffix or another combining form.

When to Use a Combining Vowel

To determine the need for a combining vowel, notice whether the following word part ...

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