1 Word Parts and Rules

Medical terms are built from word parts. Those word parts are prefix, suffix, and combining form vowel. When a word root is combined with a combining form vowel, the word part is referred to as a combining form.

Identifying Word Parts in Medical Terms

By the end of this book, you will have identified hundreds of word parts within medical terms. Let’s start with some common medical terms that many non-medically trained people may be familiar with.

Examples

Biology
bi/o/logy
bi/o is a combining form that means life.
–logy is a suffix that means study of.

The definition of biology is the study of life.

Autograph
aut/o/graph
aut/o is a combining form that means self
-graph is a suffix that means something that is written.

The literal meaning of the word autograph is a record of self. You can see that this literal meaning helps us understand the definition of autograph which is a handwritten signature, esp that of a famous person. (the free dictionary)

Intravenous
Intra/ven/ous
intra- is a prefix that means within.
ven/o– is a combining form that means vein.
-ous is a suffix that means pertaining to

The definition of intravnous is pertaining to within a vein.

Notice, when breaking down words it helps to add slashes between word parts and a slash on each side of a combining form vowel.

Language Rules

Language rules are a good place to start when building a medical terminology foundation. Many medical terms are built from word parts and can be translated literally. At first, literal translations sound awkward. The awkwardness will slip away once you build a medical vocabulary and become proficient at using it. For example, suffixes will no longer be stated and will be assumed. The definition of intravenous then becomes within the vein.

Stay literal when applicable since you are at the beginning of building your medical terminology foundation. It should be noted that, as with all language rules, there are always exceptions, and we refer to those as rebels.

Language Rules for Building Medical Terms

1. When combining two combining forms, you keep the combining form vowel.
2. When combining a combining form with a suffix that begins with a consonant, you keep the combining form vowel.

Examples

• Following rule 1, when we join combining form gastr/o (meaning stomach) with the combining form enter/o (meaning intestines) we keep the combining form vowel o.
• Following rule 2, when we join the combining form enter/o (meaning intestines) with the suffix -logy (that starts with a suffix and means the study of) we keep the combining form vowel o.

Examples

• Following rule 3, notice that when combining the combining form ven/o (meaning vein) with the suffix -ous ( that starts with a vowel and means pertaining to) we drop the combining form vowel o.
• Following rule 4, the prefix intra- (meaning within) is at the beginning of the medical term with no combining form vowel used.

Examples

• Following rule 5, notice that the definition begins with the suffix -ous (that means pertaining to), then continues left to right, starting with the prefix Intra- (meaning within) and the combining form ven/o (meaning vein).

References

• Anatomy and Physiology (on OpenStax), by Betts et al. and is used under a CC BY 4.0 international license. Download and access this book for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction

Word part at the beginning of a medical term that changes the meaning of the word root.

A word part added to the end of a word that changes the meaning of the word root.

The combining form vowel is used to join word parts and to ease pronunciation. The most common combining form vowel is an "o," but sometimes it is an "i" or an "e".

the foundational meaning of a word.

A word root with a combining form vowel