The Collaborative International Dictionary of English v.0.48:

Upholster \Up*hol"ster\, v. t. [See Upholsterer.]
   To furnish (rooms, carriages, bedsteads, chairs, etc.) with
   hangings, coverings, cushions, etc.; to adorn with
   furnishings in cloth, velvet, silk, etc.; as, to upholster a
   couch; to upholster a room with curtains.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Upholster \Up*hol"ster\, n.
   1. A broker. [Obs.] --Caxton.
      [1913 Webster]

   2. An upholsterer. [Obs.] --Strype.
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The Collaborative International Dictionary of English v.0.48:

Upholsterer \Up*hol"ster*er\, n. [A substitution for older
   upholder, in OE., broker, tradesman, and formerly also
   written upholster, upholdster. See Upholder, and
   -ster.]
   One who provides hangings, coverings, cushions, curtains, and
   the like; one who upholsters.
   [1913 Webster]

   Upholsterer bee. (Zool.) See Poppy bee, under Poppy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

upholster
    v 1: provide furniture with padding, springs, webbing, and
         covers