adj

• (linguistics) Concerning the vocabulary, words, sentences or morphemes of a language.
  "So, it seems clear that the idiosyncratic restrictions relating to the range of complements which a Preposition does or does not permit are directly analo- gous to the parallel restrictions which hold in the case of Verbs. The restric- tions concerned are not categorial in nature (i.e. they are not associated with every single item belonging to a given category): on the contrary, they are lexical in nature (that is to say, they are properties of individual lexical items, so that different words belonging to the same category permit a different range of complements)."
• (linguistics) Concerning lexicography or a lexicon or dictionary.
• (linguistics) Denoting a content word as opposed to a function word.
  "a lexical verb"
• (chiefly computing) Relating to alphabetical order or a generalization thereof.