Hash may refer to:

  • Hashish, a psychoactive drug
  • Hash (food), a coarse mixture of ingredients
  • Hash House Harriers, a running club
Hash mark
  • Hash marks, a marking on hockey rinks and gridiron football fields
  • Hatch mark, a form of mathematical notation
  • Service stripe, a military decoration
  • Tally mark, a counting notation
In linguistics
  • Hash symbol or hash mark, the glyph #
  • Hashtag, a form of metadata often used on social networking websites
In computing
  • Hash function, a derivation of data, notably seen in cryptographic hash functions
  • Hash table, a data structure
  • hash (Unix), an operating system command
  • Fragment identifier, in computer hypertext, a string of characters that refers to a subordinate resource
  • Geohash, a spatial data structure which subdivides space into buckets of grid shape
  • Hash chain, a method of producing many one-time keys from a single key or password
In media
  • Hash (film), a 2005 film