Source : Webster's Revised Unabridged Dictionary (1913)

Ordinal \Or"di*nal\, a. [L. ordinalis, fr. ordo, ordinis, order.
   See {Order}.]
   1. Indicating order or succession; as, the ordinal numbers,
      first, second, third, etc.

   2. Of or pertaining to an order.

Ordinal \Or"di*nal\, n.
   1. A word or number denoting order or succession.

   2. (Ch. of Eng.) The book of forms for making, ordaining, and
      consecrating bishops, priests, and deacons.

   3. (R. C. Ch.) A book containing the rubrics of the Mass.
      [Written also {ordinale}.]

Source : WordNet®

ordinal
     adj 1: of or relating to a taxonomic order; "family and ordinal
            names of animals and plants"
     2: being or denoting a numerical order in a series; "ordinal
        numbers"; "held an ordinal rank of seventh" [ant: {cardinal}]
     n : the number designating place in an ordered sequence [syn: {ordinal
         number}, {no.}]

Source : Free On-Line Dictionary of Computing

ordinal
     
         An {isomorphism class} of {well-ordered set}s.
     
        (1995-03-10)