The Collaborative International Dictionary of English v.0.48:

Hundredth \Hun"dredth\, a.
   1. Coming last of a hundred successive individuals or units.
      [1913 Webster]

   2. Forming one of a hundred equal parts into which anything
      is divided; the tenth of a tenth.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Hundredth \Hun"dredth\, n.
   One of a hundred equal parts into which one whole is, or may
   be, divided; the quotient of a unit divided by a hundred.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hundredth
    adj 1: the ordinal number of one hundred in counting order [syn:
           hundredth, centesimal, 100th]
    n 1: position 100 in a countable series of things
    2: one part in a hundred equal parts [syn: one-hundredth,
       hundredth, one percent]