The term "oyatsu" (おやつ), also written in katakana (one of the Japanese syllabaries) as オヤツ, refers to an afternoon snack that was originally eaten at yatsudoki (approximately 2 p.m.) according to the old Japanese way of counting time.
おやつ（片仮名でオヤツとも）とは、八つ時（午後2時頃）に食べる間食のことを指す。