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a combining form meaning “arm,” “upper arm,” used in the formation of compound words: brachiopod.
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Also especially before a vowel, brachi-.

Origin of brachio-

Combining form representing Latin brāchium and Greek brachī́ōn
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does brachio- mean?

Brachio- is a combining form used like a prefix meaning “arm” or “upper arm.” It is often used in medical and scientific terms, especially in anatomy and in zoology.

Brachio- comes from the Greek brachī́ōn, meaning “arm.” A medical term for the upper arm is brachium, from Latin and related to the Greek brachī́ōn.

What are variants of brachio-?

When combined with words or word elements that begin with a vowel, brachio- becomes brachi-, as in brachialgia.

Examples of brachio-

A brachiosaurus was a huge sauropod dinosaur: it was over 80 feet (24 meters) long and about 40 feet (12 meters) tall, thanks to its massive neck. Its name comes from the New Latin Brachiosaurus, which dates back to 1903.

The brachio- part of brachiosaurus, using the equivalent form of brachio- in New Latin, means “arm.” The -saurus part of brachiosaurus is used to name extinct reptiles and dinosaurs, from the Greek saûros, meaning “lizard.” Brachiosaurus literally translates to “arm lizard.” The name is an allusion to the unusual length of the humerus (upper arm bone) relative to the femur (upper leg bone) in this creature.

What are some words that use the combining form brachio-?

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

Break it down!

The combining form -cephalic refers to the “head.” What parts of the body does the brachiocephalic artery supply blood to?

How to use brachio- in a sentence

British Dictionary definitions for brachio-


before a vowel brachi-

combining form
indicating a brachiumbrachiopod
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for brachio-


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