This is the 7970th most frequent Japanese word.
大吉
"Great fortune" or "excellent luck."
In this sentence, '大吉' is used to indicate a day of outstanding luck or fortune, commonly associated with auspicious occasions in Japan.
今日は大吉の日ですよ。
Today is a day of great fortune.
In this case, '大吉' is used as a proper noun, serving as the name of a pet, combining its meaning of great fortune with a personalized touch.
大吉という名前の猫を飼っています。
I have a cat named 'Daikichi'.
Here, '大吉' refers to the best possible result one can get on an omikuji (a traditional Japanese fortune slip), expressing joy and expectation.