Yonk
A word used by History Monks such as Lu-Tze to denote quite a long length of time (although Lu-Tze maintains it's one of the Abbot's). It is possible this imprecise measurement is used for the educative bamboozlement of young novices, in order to get them really thinking about things.
Annotation
A yonk is a round world expression as in "Ain't seen 'im in yonks".