v math: determine the length of
v reduce to a fine, unmixed, or pure state; separate from extraneous matter or cleanse from impurities
v bring, lead, or force to abandon a wrong or evil course of life, conduct, and adopt a right one
v set straight or right
v make right or correct
v convert into direct current
v. 改正, 矫正( rectify的第三人称单数 ); 精馏