1 : not less than a specified amount, level, etc.
At least once a year, we visit our grandparents.
We meet at least once a month. = We meet once a month at least.
You must be at least 21 years of age to enter.
2 — used to say that something (such as a bad situation) could be or have been worse
The weather was cold, but at least it didn't rain.
I was tired and hungry, but at least I was free.
We don't have much money, but at least we still have each other.
3 — used to indicate the smallest or easiest thing that someone can or should do
Well, he could have at least apologized.