1. central; at or near the middle point: in the mid nineties of the last century.
2. Phonetics having a tongue position intermediate between high and low: beet, bet, and bat have high, mid, and low vowels respectively.
[ME; OE midd, c. OHG mitti, Icel. midhr, Goth. midjis middle; akin to L medius, Greek mésos, Skt madhya middle]