noun (n)

• a shortage of rainfall(noun.state)

  Example:
  Farmers most affected by the drought hope that there may yet be sufficient rain early in the growing season.
  

  Synonym:
  drouth
  

  source: wordnet30
• a prolonged shortage(noun.time)

  Example:
  When England defeated Pakistan it ended a ten-year drought.
  

  source: wordnet30
• Dryness; want of rain or of water; especially, such dryness of the weather as affects the earth, and prevents the growth of plants; aridity.(noun)

  source: webster1913