A compensatory day off taken later in lieu of working on a holiday or regular day off (often called 'daikyū').
昨日は会社の都合で出勤したので、明日代休を取ります。
I worked yesterday because of company needs, so I'll take a compensatory day off tomorrow.
代休は就業規則に従って申請しないと認められない場合がある。
Compensatory leave may not be granted unless you apply according to company rules.
子どもの行事があるので、代休を使って午後に学校へ行きます。
I will use a compensatory day off to go to my child's school event in the afternoon.
代休は有給休暇とは別に付与されることが多い。
Compensatory leave is often granted separately from paid vacation days.