How to Find Parts of Words in Medical Terminology

By Beverley Henderson, Jennifer Lee Dorsey

Medical terminology can seem a little overwhelming at times. Just remember, there are three major parts of every medical term you can investigate so that you can more easily discover its meaning.

Identifying word elements

At the beginning of a medical term, you often (but not always) find the prefix, which can indicate the direction, the where, the when, and the amount.

Next comes the root word, indicating the body part involved. Some root word meanings are obvious and easy to understand, like arteri/o for artery, abdomin/o for abdomen, testicul/o for testicle, and tonsill/o for tonsil. Many are not so easy: What about blephar/o for eyelids, aden/o for gland, nephr/o for kidney, hepat/o for liver, or oophor/o for ovary?

The suffix at the end of a term is often your first clue to the definition of the term. It can indicate a procedure, a condition, or a disease.

There is always a suffix at the end of a medical term.

The meaning of a suffix, just as with some root words, may not be obvious. It’s important to remember that the suffix always has the same meaning, no matter what root word it’s tacked on to.

The suffix, then, is the first place to look when trying to analyze or break down a medical term. From the suffix, back up to the prefix, if there is one, and finally, look at the root word.

Defining the prefix

The prefix and suffix are “adjectives,” in a way, telling you something about the root word in the middle. Changing the prefix or the suffix changes the meaning of the term.

Let’s look at some commonly used prefixes, pre- (before), peri- (during), and post- (after or following), all coupled with the same term. Watch how the prefix changes the time frame.

Consider the word operative for example, beginning with preoperative, referring to the time period or events before an operative procedure. Changing the prefix to peri- would be perioperative, indicating the time or the events around or during an operation. Then changing the prefix to post- would result in postoperative, meaning the time or events after the surgery is completed. By using the three different prefixes, these words sound somewhat alike but are quite different in their meanings.

Some prefixes often mistaken one for another are the prefixes ab-, meaning “away from,” and ad-, meaning “towards” or “in the direction of.”

Remember abduction, a kidnapping, or being taken away, as a memory key to tell the two apart.

Another example is the prefix dys-, often used in medical terms. Think of dysfunctional (not the dis in discomfort). Dys- used as a prefix in front of a medical term means “difficult,” “bad,” or “painful.”

The prefix inter-, meaning “between or among,” is often mistaken for intra-,which means “within or inside.” Think of an interstate highway, winding between and among states. For intra-, think of an intrauterine contraceptive device, used within or inside the uterus.

The definition of a prefix is always the same, no matter what it’s paired with.

Prefixes are joined to a root word without the use of a hyphen, even when a double vowel results as in perioperative,intrauterine. The only exception to this rule is that a hyphen is used when the prefix joins up with a proper name: non-Hodgkin’s lymphoma.

Defining the root word

The root word describes the body parts involved in the medical term. So, if you are having a hard time remembering the meaning of a word, you can parse it out by identifying the root word. Take a look at some common examples:

  • Arthro: Joint

  • Colo: Colon

  • Laryngo: Larynx

  • Myelo: Bone marrow

  • Myo: Muscle

  • Neuro: Nerve

  • Osteo: Bone

As always, a little memory work is needed here.

Medical terms always have a suffix but not always a prefix. Some medical terms have a combination of two or more root words, coupling multiple body parts together: for example, hepatospleno comes from hepato (liver) and spleno (spleen).

Identifying the combining vowel

The combining vowel, usually an o, joins the root word to a suffix. If a suffix begins with a vowel, the combining vowel o is not used, because it would create a double vowel.

Take the root word neuro (for “nerve,” right?) as an example. Let’s join it to the suffix –itis, which means “inflammation.” Using the combining vowel o to join these together, you would have neuroitis, which is not only difficult to pronounce but also contains a double vowel. Therefore, the o is dropped, and inflammation of a nerve becomes neuritis.

Defining the suffix

As you know, the suffix indicates a procedure, disease, disorder, or condition, and you look at it first. For example, the suffix -itis is common. It means “inflammation,” so every time you see -itis, you know it means something is inflamed. Taking a word that you know — tonsil — you know that tonsillitis means “inflammation of the tonsil.”

The commonly used suffix -ectomy means “surgical removal or excision of.” When you put -ectomy with tonsil, you have tonsillectomy, removal of the tonsils.

The word tonsil (or tonsils) has only one l, but when it’s made into a combining form such as tonsillitis or tonsillectomy, the l is doubled. Tonsillitis is a commonly misspelled medical word. More memory work!

Suffixes as “adjectives” help describe the root word. For instance, the suffixes -al, -ic, -ous, and -eal are all suffixes that mean “pertaining to.” The suffix -ologist refers to “one who studies or practices a specialized medical field.” The suffix -ology is “the study of.” The common suffix -pathy means “disease.”

Take an easily identifiable root word, cardio or cardiac, meaning “heart,” and apply different suffixes. Cardiology is the study of heart diseases. The cardiologist is the physician who practices cardiology, and cardiopathy means some form of heart disease.