1580s, "of moderate degree or quality, neither good nor bad," from Middle 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.