(1) To set right; remedy. (2) To correct by removing errors; revise.
Example:
You must try to rectify this unfortunate situation before anyone else gets hurt.
We rectify something by straightening it out or making it right. We might rectify an injustice by seeing to it that a wrongly accused person is cleared. An error in a financial record can be rectified by replacing an incorrect number with a correct one. If the error is in our tax return, the Internal Revenue Service will be happy to rectify it for us. We might then have to rectify the impression that we were trying to cheat on our taxes.