an official statement issued by one intelligence agency to other agencies. It states that an individual or a group is unreliable for one or more reasons or purposes. This is essentially a directive for the recipient to disregard or "burn" all information derived from that individual or group.
"The CIA issued a burn notice on the defector from the Soviet Union after most of his stories were found to be false."
When more than one person is over a house that is vast in size and one eventually leaves without the other because they assume they've already left due to the fact that they haven't run into each other in awhile.
George: "oh, you're still here!"
George" "your friend took off, she thought you left, so..."
George: "that's what happens in a big house. It's called the big house problem."