noun
Direct borrowing from Dutch 'zondag'. Used in historical or regional contexts, especially in Nagasaki where Dutch influence was strong. Not standard modern Japanese for Sunday.
from Dutch zondag
長崎では昔、日曜日のことを「ドンタク」と呼んでいた。
In Nagasaki, they used to call Sunday 'dontaku'.
noun
Extended meaning from Sunday to any holiday or day off. Mainly survives in the name of the Hakata Dontaku festival (博多どんたく). Not used in everyday conversation.
博多どんたくは毎年五月に開催される大きな祭りだ。
Hakata Dontaku is a big festival held every May.