1.Prepositional phraseAfter 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."
2.Prepositional phraseIn 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."