Of ordinary or undistinguished quality. See Synonyms at average.
[French médiocre, from Latin mediocris : medius, middle; see medhyo- in the Appendix of Indo-European roots + ocris, a rugged mountain; see ak- in the Appendix of Indo-European roots.]
Word History: Belying the very meaning of the word, the adjective mediocre has a remarkable and unexpected etymology. Mediocre ultimately comes from Latin mediocris, which meant "middling, ordinary, unremarkable." The Latin word in turn is a compound based on a rather concrete metaphor—we often find that abstract words are rooted in vivid comparisons when we trace the history of words back till we hit bedrock. In this case, the bedrock is a Latin word for "mountain." Mediocris is a compound of the adjective medius, "half" or "in the middle," and ocris, "rugged mountain." Something that is mediocre is only midway up a mountain or rises up to only half a mountain's height, as it were—the thing goes just halfway to the highest point of excellence. The resemblance between the Latin word medius and English words like middle and midway is no accident. They are all ultimately descended from the Proto-Indo-European word *medhyo-, "middle."
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.