A day off or public holiday; commonly refers to weekends and national holidays when people are not working.
休日は家族と公園に行くことが多い。
On days off I often go to the park with my family.
祝日が重なって今年のGWは長い休日になった。
Several national holidays fell together, so this year's Golden Week became a long holiday.
休日出勤が続いて疲れている。
I'm tired from working on my days off.