What is the meaning of rectify?

verb

• Math: determine the length of.
  • usage: "rectify a curve"
• Reduce to a fine, unmixed, or pure state; separate from extraneous matter or cleanse from impurities.
  • usage: "refine sugar"
  • synonyms: refine
• Bring, lead, or force to abandon a wrong or evil course of life, conduct, and adopt a right one.
  • usage: "The Church reformed me"; "reform your conduct"
  • synonyms: reform, reclaim, regenerate
• Set straight or right.
  • usage: "remedy these deficiencies"; "rectify the inequities in salaries"; "repair an oversight"
  • synonyms: remediate, remedy, repair, amend
• Make right or correct.
  • usage: "Correct the mistakes"; "rectify the calculation"
  • synonyms: correct, right
• Convert into direct current.
  • usage: "rectify alternating current"