noun (n)

• any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water(noun.substance)

  Synonym:
  base
  

  source: wordnet30
• a mixture of soluble salts found in arid soils and some bodies of water; detrimental to agriculture(noun.substance)

  source: wordnet30
• Soda ash; caustic soda, caustic potash, etc.(noun)

  source: webster1913
• Soluble mineral matter, other than common salt, contained in soils of natural waters.(noun)

  source: webster1913