What is the meaning of latch on?

verb

• Take hold of or attach to.
  • usage: "The biochip latches onto the genes"
• Adopt.
  • usage: "take up new ideas"
  • synonyms: take up, fasten on, hook on, seize on
• Understand, usually after some initial difficulty.
  • usage: "She didn't know what her classmates were plotting but finally caught on"
  • synonyms: catch on, get wise, get onto, tumble, cotton on, twig, get it