1. Time spent thinking about someone who is not around; whether remembering time shared in the past, or having fantasies of what could happen with them in the future.
2. Time spent reading, listening, or watching the work produced by someone who is dead. Also, time spent having imaginary conversations with someone who is dead.
Examples: I know he was dead before I was even born, but the ghost time I've spent with Henry David Thoreau makes it feel like we're old friends.
He hardly even knows who she is, but he's spent so much ghost time with her that he thinks he's in love.
Literary Reference: In the Catcher in the Rye, Holden Caufield spends ghost time with his deceased brother Allie whenever he feels overcome by negative feelings.