1.
lucky day; auspicious day; most favorable day
The most auspicious day in the traditional Japanese six-day calendar cycle (六曜 rokuyo). Considered the best day for weddings, business openings, and other important events.
Cultural note
大安 is part of the 六曜 (six-day cycle) calendar system used in Japan for fortune-telling. The six days are: 大安 (most lucky), 友引 (partly lucky), 先勝 (morning lucky), 先負 (afternoon lucky), 赤口 (mostly unlucky), and 仏滅 (most unlucky). Many Japanese calendars still include these designations.