Rel

A rel was a Dalek unit of time measurement. A rel was roughly equivalent to one second. (DW: Evolution of the Daleks)

Behind the Scenes
The rel first appeared in the Peter Cushing 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.