noun (n)

• the leaves of the shrub Catha edulis which are chewed like tobacco or used to make tea; has the effect of a euphoric stimulant(noun.artifact)

  Example:
  In Yemen kat is used daily by 85% of adults.
  

  Synonym:
  african tea, arabian tea, cat, khat, qat, quat
  

  source: wordnet30
• An Arabian shrub (Catha edulis) the leaves of which are used as tea by the Arabs.(noun)

  source: webster1913