rectification

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(civil engineering) A new alignment to correct a deviation of a stream channel or bank.
(electricity) The process of converting an alternating current to a unidirectional current.
(geology) The simplification and straightening of the outline of an initially irregular and crenulate shoreline through the cutting back of headlands and offshore islands by marine erosion, and through deposition of waste from erosion or of sediment brought down by neighboring rivers.
(graphic arts) The transformation of a photograph onto a horizontal plane so as to remove or correct displacements (distortions in perspective) by tilt.

Conversion of electric current from alternating to direct (unidirectional).