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.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Tapering \Ta"per*ing\, a. Becoming gradually smaller toward one end. -- Ta"per*ing*ly, adv.

Source: Webster's Revised Unabridged Dictionary (1913)