Run-off election
Election to select a winner following a primary election or a general election, in which no candidate in the contest received the required minimum percentage of the votes cast. The two candidates receiving the most votes for the contest in question proceed to a runoff election.
Source: Election Terminology Glossary - Draft, National Institute of Standards and Technology (NIST), https://pages.nist.gov/ElectionGlossary/; Glossary of terms database, U.S. Election Assistance Commission, https://www.eac.gov/glossary/