\Me"di*um\, n.; pl. L. {Media}, {E}. {Mediums}. [L.
medium the middle, fr. medius middle. See {Mid}, and cf.
{Medius}.]
1. That which lies in the middle, or between other things;
   intervening body or quantity. Hence, specifically:
   (a) Middle place or degree; mean.
             The just medium . . . lies between pride and
             abjection.                        --L'Estrange.
   (b) (Math.) See {Mean}.
   (c) (Logic) The mean or middle term of a syllogism; that
       by which the extremes are brought into connection.
2. A substance through which an effect is transmitted from
   one thing to another; as, air is the common medium of
   sound. Hence: The condition upon which any event or action
   occurs; necessary means of motion or action; that through
   or by which anything is accomplished, conveyed, or carried
   on; specifically, in animal magnetism, spiritualism, etc.,
   a person through whom the action of another being is said
   to be manifested and transmitted.
         Whether any other liquors, being made mediums, cause
         a diversity of sound from water, it may be tried.
                                               --Bacon.
         I must bring together All these extremes; and must
         remove all mediums.                   --Denham.
3. An average. [R.]
         A medium of six years of war, and six years of
         peace.                                --Burke.
4. A trade name for printing and writing paper of certain
   sizes. See {Paper}.
5. (Paint.) The liquid vehicle with which dry colors are
   ground and prepared for application.
{Circulating medium}, a current medium of exchange, whether
   coin, bank notes, or government notes.
{Ethereal medium} (Physics), the ether.
{Medium of exchange}, that which is used for effecting an
   exchange of commodities -- money or current
   representatives of money.

\Me"di*um\, a.
Having a middle position or degree; mean; intermediate;
medial; as, a horse of medium size; a decoction of medium
strength.