Which word sounds like a letter of the alphabet and means a former spouse?

Which Leslie Nielsen film comedy series was based on the TV show "Police Squad!"? Which ruthless Russian ruled as tsar from 1547 to 1584? Complete the title of Marcus Pfister's picture book about sharing: "The Rainbow ___". An orange letter C with white trim is the logo of which NFL team? Which word means both a level of stability and an elevated flat surface? A libel trial is the focus of which "Exodus" author's 1970 novel "QB VII"? A library at the UN serves as a memorial to which secretary-general, killed in a 1961 plane crash? A library in a villa in Herculaneum, buried by which volcano's eruption in A.D. 79, was found in the mid-1700s?