One of the six traditional calendar days (rokuyō) considered very auspicious for events such as weddings or moving; often shortened to 大安.
結婚式は大安吉日に行う予定だから、会場を早めに予約した。
Since the wedding is planned on a taian kichijitsu, I reserved the venue early.
引っ越しは大安吉日を選ぶ人が多いが、日程の都合も考慮が必要だ。
Many people choose to move on an auspicious day, but scheduling constraints must also be considered.
今日は大安吉日だから、商売始めに適していると言われる。
Today is an auspicious day, so it's said to be suitable for starting a business.