Source : Webster's Revised Unabridged Dictionary (1913)

Curtain \Cur"tain\, v. t. [imp. & p. p. {Curtained} (-t?nd; 48);
   p. pr. & vb. n. {Curtaining}.]
   To inclose as with curtains; to furnish with curtains.

         So when the sun in bed Curtained with cloudy red.
                                                  --Milton.