What is the meaning of call back?

verb

• Cause to be returned.
  • usage: "recall the defective auto tires"; "The manufacturer tried to call back the spoilt yoghurt"
  • synonyms: recall, call in, withdraw
• Recall knowledge from memory; have a recollection.
  • usage: "I can't remember saying any such thing"; "I can't think what her last name was"; "can you remember her phone number"; "Do you remember that he once loved you"; "call up memories"
  • synonyms: remember, retrieve, recall, call up, recollect, think
• Return or repeat a telephone call.
  • usage: "I am busy right now-can you call back in an hour"; "She left a message but the contractor never called back"
• Summon to return.
  • usage: "The ambassador was recalled to his country"; "The company called back many of the workers it had laid off during the recession"
  • synonyms: recall