Did you mean "rectifiers" ?

You can look up the history and origin of words here:

Online Etymology Dictionary (http://www.etymonline.com/index.php?search=rectify&searchmode=none)

Seems rectify is from a Latin word Rectus which meant "Straight".

If your referring to the electronic component that rectifies AC current to DC current, and understand that AC current changes, 60 cycles would change direction 120 times per second, and is illustrated by a sine wave, you can see that using a rectifier will straighten the sine wave and produce DC current.