Definition from Wiktionary, the free dictionary
Prepositional phrase 
- (idiomatic) After a long time; eventually.
- Now that the dog has stopped barking, perhaps we can at last get some rest.
- After three hundred years had passed, at last the vampire's soul was free.
- (idiomatic) In the end; finally; ultimately.
- After all their troubles, at last they lived happily ever after.
- After exhausting all possibilities, Holmes was at last satisfied the problem was unsolvable.
- Upon balancing the account, the profit at last will hardly countervail the inconveniences that go along with it.
after a long time; eventually
in the end; finally; ultimately