A somewhat colloquial or old-fashioned term for a national holiday, evoking the image of flags being flown. Often used in casual conversation.
Tomorrow is a national holiday, so both school and work are off.
On national holidays, you can see national flags all around town.
Compound of 旗 (hata, 'flag') and 日 (hi, 'day'), with rendaku voicing. Refers to days when flags are traditionally displayed, i.e., national holidays.