adjective (a)

• relating to or of the nature of a zone(adj.pert)

  Example:
  The zonal frontier.
  

  Synonym:
  zonary
  

  source: wordnet30
• associated with or divided into zones(adj.all)

  Example:
  A zonal pattern of cell structure.
  Zonal division.
  

  Antonym:
  azonal
  

  source: wordnet30
• Of or pertaining to a zone; having the form of a zone or zones.(adjective)

  source: webster1913