The Collaborative International Dictionary of English v.0.48:

Lexicographic \Lex`i*co*graph"ic\
   (l[e^]ks`[i^]*k[-o]*gr[a^]f"[i^]k), Lexicographical
\Lex`i*co*graph"ic*al\ (l[e^]ks`[i^]*k[-o]*gr[a^]f"[i^]*kal), a.
   [Cf. F. lexicographique.]
   Of or pertaining to, or according to, lexicography. --
   Lex`i*co*graph"ic*al*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lexicographical
    adj 1: of or relating to lexicography [syn: lexicographic,
           lexicographical]