also: デイ · ディ
suffix
Suffix attached to nouns to form names of special days, observances, or holidays. Often used in commercial or promotional contexts.
来月のバレンタインデーに何をあげる？
What will you give on Valentine's Day next month?
この店では毎週金曜日はポイント2倍デーです。
At this store, every Friday is double points day.
noun-modifying (irregular)
Prenominal element used in compounds to indicate something occurring during the day, as opposed to night. Most commonly seen in デーゲーム (day game).
See also: デーゲーム
今日の試合はデーゲームだから、暑さ対策を忘れずに。
Today's match is a day game, so don't forget to prepare for the heat.
Native Japanese word for 'day' or 'sun'; used in many common words and not limited to suffix or prenominal use.
Alternate spelling of the same loanword; interchangeable in many compounds, though デー is more frequent.
Borrowed from English 'day'. The spelling デー reflects a long vowel adaptation, while デイ preserves the original diphthong. ディ is an irregular variant.