2.2 Medical Terminology Basics
Word Parts
Medical terms are built from word parts, which are also called component parts. These parts are prefixes, roots, suffixes, and combining vowels.
Below you will see definitions of the component parts of medical terms. Throughout this chapter, you will learn many different word parts and apply that knowledge in the review activities at the end of the chapter.
Key Concepts
- A prefix goes at the front of the term and changes the meaning.
- Example: dys– means “bad,” “painful,” “difficult,” or “abnormal”
- Notice that a prefix always has a “-” after it when not in a medical term. This lets you know that the prefix needs something after it.
- Not all medical terms have a prefix.
- A suffix goes at the end of the term and changes the meaning.
- Example: –ology means “study of”
- Notice that a suffix always has a “-” before it when not in a medical term. This lets you know that the suffix needs something before it.
- All medical terms have a suffix.
- The root gives the essential meaning of the term.
- Example: cardi means “heart”
- A medical term may have one or more roots. In some rare cases, a term may not have a root because the root is embedded in the suffix.
- A combining vowel has no meaning but connects roots to suffixes and roots to other roots.
- A combining vowel is almost often an o, but can also be an a or an i.
Once you become more familiar with all the common word parts, you will be able to use this knowledge to break down any medical term into its component parts and determine its meaning. Although you have just started learning medical terminology, the example below demonstrates how a medical term can be broken apart so you can understand its meaning.
Example
The medical term, hemigastrectomy can be broken into the following component parts:
hemi/gastr/ectomy
The prefix hemi- means “half,” the root gastro means “stomach,” and -ectomy is a suffix that means “removal.” If you put it all together, the term hemigastrectomy means “removal of half the stomach.”
Language Rules for Building Medical Terms
There are a few rules that should be followed when interpreting and writing medical terms. It is important to memorize these rules in order to prevent errors. It is also important to note that with any language, there are always exceptions to the rules. Once you start to build a medical vocabulary and become proficient at using it, understanding medical terminology will become much easier.
Since you are at the beginning of building your medical terminology knowledge base, it is best to be literal when learning medical terms. Later, when you become more proficient at using medical terminology, the initial awkwardness will disappear. For example, suffixes will no longer be stated and will be assumed, such as the literal definition of intravenous, which is “pertaining to within the vein.” As you become more familiar with medical terminology, you will read this as “within the vein.” So let’s begin by learning the language rules for medical terminology.
Language Rules
Rule 1: When joining two roots, keep the combining vowel.
Rule 2: When joining a root with a suffix that begins with a consonant, keep the combining vowel.
Example
gastr/o/enter/o/logist – “specialist in the stomach and intestines”
- Following Rule 1, when we join the root gastro (meaning “stomach”) with the root entero (meaning “intestines”), we keep the combining vowel o.
- Following Rule 2, when we join the combining form entero (meaning “intestines”) with the suffix -logist (which starts with a consonant and means “specialist”), we keep the combining form vowel o.
Rule 3: When joining a root with a suffix that begins with a vowel, drop the combining vowel.
Rule 4: A prefix goes at the beginning of the word, and no combining vowel is used.
Example
intra/ven/ous – “pertaining to within the vein”
- Following Rule 3, notice that when combining the root veno (meaning “vein”) with the suffix -ous (which starts with a vowel and means “pertaining to”), we drop the combining vowel o.
- Following Rule 4, the prefix intra- (meaning “within”) is at the beginning of the medical term with no combining vowel used.
Rule 5: When defining a medical word, start with the suffix (end of the term), then work from left (the start of the term) to right, stating the word parts. You may need to add filler words. As long as the filler word does not change the meaning of the term, you may use it for the purpose of building a medical vocabulary. Once you start to apply the word in the context of a sentence, it will be easier to decide which filler word(s) to choose.
Example
intra/ven/ous – “pertaining to within the vein” or “pertaining to within a vein”
- Following Rule 5, start with the suffix -ous (meaning “pertaining to”), then work from left to right starting with the prefix intra- (meaning “within”) and the root veno (meaning “vein”).
- Notice that we have used two different definitions that mean the same thing.
- In these examples, we do not have the context of a full sentence. For the purpose of building a medical terminology foundation, either definition of intravenous is acceptable.
Attribution
Unless otherwise indicated, material on this page has been adapted from the following resource:
Sturdy, L., & Erickson, S. (2022). The language of medical terminology. Open Education Alberta. https://pressbooks.openeducationalberta.ca/medicalterminology/, licensed under CC BY-NC-SA 4.0
