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a combining form with the meaning “rod,” used primarily in biology to form generic names of bacteria: aerobacter; arthrobacter.
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Origin of -bacter

<New Latin, masculine noun coined as variant of neuter bactrum<Greek báktron;see bacterium
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does -bacter mean?

The combining form -bacter is used like a suffix meaning “rod.” It is often used in scientific terms, especially in biology to name bacteria.

The form -bacter comes from Greek báktron, meaning “stick.” Discover how the word for “stick” came to denote microorganisms at our entry for bacterium.

From a related Greek word, baktḗria, which means “staff” or “cane,” English inherits the combining forms bacter-, bacteri-, and bacterio-. Want to learn more? Check out our Words That Use articles for all three forms.

Related to both báktron and baktḗria is the Latin noun baculum, “staff,” the source of both the combining form bacill-, which refers to a type of rod-shaped bacteria, and baguette, a rod-shaped loaf of bread.

Examples of -bacter

One example of a scientific term that features -bacter is aerobacter, a type of short, rod-shaped bacterium. The term comes from Latin aerobacter, which uses the equivalent of the form -bacter.

The form aero- means “air,” while -bacter means “rod,” so aerobacter literally translates to “air rod.” Can you guess where these bacteria are thought to live?

What are some words that use the combining form –bacter?

What are some other forms that -bacter may be commonly confused with?

Break it down!​

The combining form arthro- means “joint.” With this in mind, what does the soil bacterium Arthrobacter look like?

Medical definitions for -bacter


Variant ofbacterio-
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.