What is the meaning of unit?

noun

• Any division of quantity accepted as a standard of measurement or exchange.
  • usage: "the dollar is the United States unit of currency"; "a unit of wheat is a bushel"; "change per unit volume"
  • synonyms: unit of measurement
• An individual or group or structure or other entity regarded as a structural or functional constituent of a whole.
  • usage: "the reduced the number of units and installations"; "the word is a basic linguistic unit"
• An organization regarded as part of a larger social group.
  • usage: "the coach said the offensive unit did a good job"; "after the battle the soldier had trouble rejoining his unit"
  • synonyms: social unit
• A single undivided whole.
  • usage: "an idea is not a unit that can be moved from one brain to another"
• A single undivided natural thing occurring in the composition of something else.
  • usage: "units of nucleic acids"
  • synonyms: building block
• An assemblage of parts that is regarded as a single entity.
  • usage: "how big is that part compared to the whole"; "the team is a unit"
  • synonyms: whole