1. A firearm mechanism requiring the hammer to be manually cocked before each shot
The cowboy's revolver was a single action pistol.
A pistola do cowboy era uma arma de ação única.
2. A single movement or operation performed without repetition
He accomplished the task with a single action.
Ele completou a tarefa com uma ação única.
3. In law, a lawsuit or legal proceeding concerning one cause of action
The single action lawsuit was resolved quickly.
A ação única foi resolvida rapidamente.