(verb) (auxiliary) A syntactic marker.
"When nothing is done, nothing is left undone."
"They will only care when you're gone."
"What's done cannot be undone."
"What’s done is done, don’t go back dancing with your ghosts and strive to go onwards."
"I don’t stop when I’m tired. I only stop when I’m done."
"I have such a big heart, but once I stop caring - its wrap."
"While they were saying it couldn't be done, it was done."