The Nol toe (놀토), it means a Saturday to rest in 5 days a week work system (노는 토요일 play Saturday).
It is compound word of 노는 (Play/ no nun) and 토요일 (Saturday/ Toe yoil)
Korean school was supposed to rest school every Saturday from 2012.
And absent from school on Saturday every other week from 2005 but, run weekly from 2012.
And it is normally using now