noun
lesson day; practice day
Refers to a scheduled day for a lesson or practice, especially in traditional arts, martial arts, or music.
来週の稽古日をカレンダーに書いておいてください。
Please write down next week's lesson day on the calendar.
今日はお茶の稽古日です。
Today is the day for my tea ceremony lesson.
練習日 is a more general term for 'practice day' used in sports or music, while 稽古日 often implies traditional arts or disciplined training.
Compound of 稽古 (keiko, 'practice, lesson') and 日 (bi, 'day'). The reading けいこび follows rendaku voicing of ひ to び.