Rel

A rel was a Dalek unit of time measurement. A rel was slightly longer than one Earth second. (DW: Evolution of the Daleks)

Behind the Scenes
The concept of a 'Rel' first appeared in the movie Dr. Who and the Daleks, but never appeared in the TV series until the 2006 episode Doomsday, in which Dalek Sec told the other Daleks of the Cult of Skaro to rewind a recording back 9 rels.