Mediocre
late 16th century: from French médiocre, from Latin mediocris ‘of middle height or degree’, literally ‘somewhat mountainous’, from medius ‘middle’ + ocris ‘rugged mountain’.
wiktionary
From the late Middle English medioker, from the French médiocre, from the Middle French médiocre, from the Classical Latin mediocris(“in a middle state”, “of middle size”, “middling”, “moderate”, “ordinary”), from medius(“middle”) + ocris(“rugged mountain”); compare mediocrely and mediocrity.
etymonline
mediocre (adj.)
1580s, "of moderate degree or quality, neither good nor bad," from French médiocre (16c.), from Latin mediocris "of middling height or state, moderate, ordinary," figuratively "mediocre, mean, inferior," literally "halfway up a mountain," from medius "middle" (from PIE root *medhyo- "middle") + ocris "jagged mountain" (cognate with Greek okris "peak, point," Welsh ochr "corner, border," Latin acer "sharp;" from PIE root *ak- "be sharp, rise (out) to a point, pierce"). As a noun, "mediocre thing or person," by 1834.
