\Mesne\, a. [Cf. {Mean} intermediate.] (Law)
Middle; intervening; as, a mesne lord, that is, a lord who
holds land of a superior, but grants a part of it to another
person, in which case he is a tenant to the superior, but
lord or superior to the second grantee, and hence is called
the mesne lord.
{Mesne process}, intermediate process; process intervening
   between the beginning and end of a suit, sometimes
   understood to be the whole process preceding the
   execution. --Blackstone. Burrill.
{Mesne profits}, profits of premises during the time the
   owner has been wrongfully kept out of the possession of
   his estate. --Burrill.