What is the meaning of hold on?

verb

• Hold firmly.
  • synonyms: grasp
• Stop and wait, as if awaiting further instructions or developments.
  • usage: "Hold on a moment"
  • synonyms: stop
• Be persistent, refuse to stop.
  • usage: "he persisted to call me every night"; "The child persisted and kept asking questions"
  • synonyms: persevere, persist, hang in, hang on
• Hold the phone line open.
  • usage: "Please hang on while I get your folder"
  • synonyms: hang on, hold the line
• Retain possession of.
  • usage: "Can I keep my old stuffed animals"; "She kept her maiden name after she married"
  • synonyms: keep