Mid-key Share definition Flag When something isn't low-key or high-key, but incredibly average, so average in fact, that it deserves to be outed as being average. Have you seen Ben's wardrobe? He's mid-key a furry. Mid-key by actuallysosoberrightnow May 4, 2019 0 0 Get merch Get the Mid-key mug. Buy Now — $32.95 See more merch