What is the meaning of using up?

noun

• The act of consuming something.
  • synonyms: consumption, expenditure

verb

• Use up (resources or materials. )
  • usage: "this car consumes a lot of gas"; "We exhausted our savings"; "They run through 20 bottles of wine a week"
  • synonyms: consume, eat up, use up, eat, deplete, exhaust, run through, wipe out
• Require (time or space. )
  • usage: "It took three hours to get to work this morning"; "This event occupied a very short time"
  • synonyms: take, occupy, use up