noun (n)

• a definite length of time marked off by two instants(noun.time)

  Synonym:
  time interval
  

  source: wordnet30
• a set containing all points (or all real numbers) between two given endpoints(noun.cognition)

  source: wordnet30
• the distance between things(noun.attribute)

  Synonym:
  separation
  

  source: wordnet30
• the difference in pitch between two notes(noun.communication)

  Synonym:
  musical interval
  

  source: wordnet30
• A space between things; a void space intervening between any two objects; as, an interval between two houses or hills.(noun)

  source: webster1913
• A tract of low ground between hills, or along the banks of a stream, usually alluvial land, enriched by the overflowings of the river, or by fertilizing deposits of earth from the adjacent hills. Cf. Bottom, n., 7.(noun)

  source: webster1913