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Related to proto-: Proto-Indo-European
proto-(word root) first
Examples of words with the root proto-: prototype
Abused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary Embree
1. First in time; earliest: protolithic.
2. First formed; primitive; original: protohuman.
3. Proto- Being a form of a language that is the ancestor of a language or group of related languages: Proto-Germanic.
4. Having the least amount of a specified element or radical: protoporphyrin.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
proto-or sometimes before a vowel
1. indicating the first in time, order, or rank: protomartyr.
2. primitive, ancestral, or original: prototype.
3. (Linguistics) indicating the reconstructed earliest stage of a language: Proto-Germanic.
4. (Chemistry) indicating the first in a series of chemical compounds: protoxide.
5. (Chemistry) indicating the parent of a chemical compound or an element: protactinium.
[from Greek prōtos first, from pro before; see pro-2]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
a combining form meaning “first,” “foremost,” “earliest form of” (prototype; protoplasm); used also in the names of chemical compounds that are the first in a given series or that contain the minimum amount of an element. Also, esp. before a vowel,prot-.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.