The Collaborative International Dictionary of English v.0.48:

Venetian \Ve*ne"tian\, a. [Cf. It. Veneziano, L. Venetianus.]
   Of or pertaining to Venice in Italy.
   [1913 Webster]

   Venetian blind, a blind for windows, doors, etc., made of
      thin slats, either fixed at a certain angle in the
      shutter, or movable, and in the latter case so disposed as
      to overlap each other when closed, and to show a series of
      open spaces for the admission of air and light when in
      other positions.

   Venetian carpet, an inexpensive carpet, used for passages
      and stairs, having a woolen warp which conceals the weft;
      the pattern is therefore commonly made up of simple
      stripes.

   Venetian chalk, a white compact talc or steatite, used for
      marking on cloth, etc.

   Venetian door (Arch.), a door having long, narrow windows
      or panes of glass on the sides.

   Venetian glass, a kind of glass made by the Venetians, for
      decorative purposes, by the combination of pieces of glass
      of different colors fused together and wrought into
      various ornamental patterns.

   Venetian red, a brownish red color, prepared from sulphate
      of iron; -- called also scarlet ocher.

   Venetian soap. See Castile soap, under Soap.

   Venetian sumac (Bot.), a South European tree (Rhus
      Cotinus) which yields the yellow dyewood called fustet;
      -- also called smoke tree.

   Venetian window (Arch.), a window consisting of a main
      window with an arched head, having on each side a long and
      narrow window with a square head.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Venetian blind
    n 1: a window blind made of horizontal strips that overlap when
         closed