fortieth(n = noun.linkdef) - position 40 in a countable series of things;
is a kind of rank

   fortieth(s = adj.all) 40th - the ordinal number of forty in counting order;

1.  Following the thirty-ninth, or preceded by thirty-nine units, things, or parts. [1913 Webster]

2.  Constituting one of forty equal parts into which anything is divided. [1913 Webster]

   One of forty equal parts into which one whole is divided; the quotient of a unit divided by forty; one next in order after the thirty-ninth. [1913 Webster]