What is the meaning of lighten?

verb

• Make more cheerful.
  • usage: "the conversation lightened me up a bit"
  • synonyms: lighten up, buoy up
• Reduce the weight on; make lighter.
  • usage: "she lightened the load on the tired donkey"
• Become more cheerful.
  • usage: "after a glass of wine, he lightened up a bit"
  • synonyms: lighten up, buoy up
• Make lighter or brighter.
  • usage: "The paint will brighten the room"
  • synonyms: brighten, lighten up
• Become lighter.
  • usage: "The room lightened up"
  • synonyms: lighten up
• Alleviate or remove (pressure or stress) or make less oppressive.
  • usage: "relieve the pressure and the stress"; "lighten the burden of caring for her elderly parents"
  • synonyms: relieve