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a combining form meaning “bud, sprout,” “embryo,” “formative cells or cell layer,” used in the formation of compound words: blastosphere.
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Which sentence is correct?
Also especially before a vowel, blast- .
See also -blast.

Origin of blasto-

<Greek, combining form of blastós a bud, sprout
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What does blasto- mean?

The combining form blasto– is used like a prefix that literally means “bud, sprout.” It is often used in scientific terms, especially in anatomy and biology, to mean “embryo” or “formative cells or cell layer.”

The form blasto– comes from Greek blastós, meaning “bud” and “sprout.” The Latin translation of blastós is germen, “sprout” or “seed,” which is the source of germ, germane, and germinal. Find out more at our entry for each word.

What are variants of blasto-?

When combined with words or word elements that begin with a vowel, blasto– becomes blast, as in blastoma. When used as a suffix, the combining form blasto– is blast, as in ectoblast.

Examples of blasto-

An example of a scientific term that features the form blasto– is blastospore, “a fungal spore that arises by budding.”

The blasto– part of the word here means “bud” or “sprout.” The spore portion of the word means, well, “spore,” from Greek sporá. Blastospore literally translates to “spore bud.”

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

What are some other forms that blasto– may be commonly confused with?

Not every word that begins with the exact letters blasto-, such as blastoff, is necessarily using the combining form blasto– to denote “bud.” Learn why blastoff means “rocket launch” at our entry for the word.

Break it down!

The combining form cyte means “cell.” With this in mind, what does the medical term blastocyte literally mean?

British Dictionary definitions for blasto-


combining form
(in biology) indicating an embryo or bud or the process of buddingblastoderm

Word Origin for blasto-

from Greek blastos; see -blast
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