What is the meaning of crackling?

noun

• The residue that remains after animal fat has been rendered.
  • synonyms: greaves
• The sharp sound of snapping noises.
  • synonyms: crackle, crepitation

verb

• Make a crackling sound.
  • usage: "My Rice Krispies crackled in the bowl"
  • synonyms: crepitate, crackle
• Make a crushing noise.
  • usage: "his shoes were crunching on the gravel"
  • synonyms: crunch, scranch, scraunch, crackle
• To become, or to cause to become, covered with a network of small cracks.
  • usage: "The blazing sun crackled the desert sand"
  • synonyms: crackle