One of the six traditional calendar weekdays (rokuyō); considered an auspicious day for the whole day, often chosen for weddings, moves, openings, etc.
結婚式の日取りは大安を選んだ。
We chose a 'taian' day for the wedding.
引っ越しは大安にすると縁起がいいと言われている。
It is said that moving on a taian day brings good luck.
友人は店の開店日を大安に合わせた。
My friend scheduled the store opening on a taian day.