The Collaborative International Dictionary of English v.0.48:

Dexter \Dex"ter\ (d[e^]ks"t[~e]r), a. [L.,; akin to Gr. ?, ?,
   Skr. dakshi[.n]a (cf. daksh to be strong, suit); Goth.
   taihswa, OHG. zeso. Cf. Dexterous.]
   1. Pertaining to, or situated on, the right hand; right, as
      opposed to sinister, or left.
      [1913 Webster]

            On sounding wings a dexter eagle flew. --Pope.
      [1913 Webster]

   2. (Her.) On the right-hand side of a shield, i. e., towards
      the right hand of its wearer. To a spectator in front, as
      in a pictorial representation, this would be the left
      side.
      [1913 Webster]

   Dexter chief, or Dexter point (Her.), a point in the
      dexter upper corner of the shield, being in the dexter
      extremity of the chief, as A in the cut.

   Dexter base, a point in the dexter lower part or base of
      the shield, as B in the cut.
      [1913 Webster]