From WordNet (r) 2.0 (August 2003) [wn]:
lexical
adj 1: of or relating to words; "lexical decision task"
2: of or relating to dictionaries
From The Collaborative International Dictionary of English v.0.48 [gcide]:
lexical \lex"ic*al\ (l[e^]ks"[i^]*kal), a.
Of or pertaining to a lexicon, to lexicography, or words;
according or conforming to a lexicon. -- Lex"ic*al*ly, adv.
[1913 Webster]