The Collaborative International Dictionary of English v.0.48:

Taper \Ta"per\, v. i. [imp. & p. p. Tapered; p. pr. & vb. n.
   Tapering.]
   To become gradually smaller toward one end; as, a sugar loaf
   tapers toward one end.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tapered \Ta"pered\, a.
   Lighted with a taper or tapers; as, a tapered choir. [R.]
   --T. Warton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tapered
    adj 1: becoming gradually narrower; "long tapering fingers";
           "trousers with tapered legs" [syn: tapered, tapering,
           narrowing]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "tapered":
   acanthoid, acanthous, acicular, acuate, aculeate, aculeiform,
   acuminate, acute, barbed, cone-shaped, cornuted, cusped, cuspidate,
   hispid, horned, horny, mucronate, needle-pointed, needle-sharp,
   pointed, pronged, sharp-pointed, spiculate, spiked, spiky, spined,
   spinous, spiny, taper, tapering, tined, toothed, unbated