In a breathless month with a decade’s worth of political bombshells, the phrase “October surprise” has become a regular part of the news lexicon.

By the strictest definition, an October surprise is news specifically (and cynically) timed by one side or another to sway an election, with evidence that it changed voters’ minds and moved the polls. More loosely, the term is applied to any big, late development, deliberate or not, perhaps even ones that show no sign of altering the outcome.

Some reference sources say the phrase was first used in the 1972 presidential election, while others trace it to the 1980 campaign (the first time it was used by The New York Times). The concept, of course, predates the wording.

Here are some examples of what could be considered October surprises.

OCT. 31, 1968 President Lyndon Baines Johnson announced a halt to bombing of North Vietnam, based on his claim that peace talks had “entered a new and a very much more hopeful phase,” and he invited the government of South Vietnam and the Viet Cong to take part in negotiations. Raising hopes that the war might end soon, the announcement appeared to bolster the standing in the polls of Vice President Hubert H. Humphrey, the Democratic presidential nominee, but Humphrey still fell short in the election against former Vice President Richard M. Nixon, the Republican.