- something that is supposed to be secret but is generally known
"their love affair was an open secret"
- It is an open secret that he deals in weapons.
- Voting shall be by open ballot, by recorded vote, or by secret ballot.
- The possibility, open to Member States under that Directive, to determine specific procedures for contracts declared secret when their performance must be accompanied by special security measures or when the protection of the Member State so requires, should be made available to the Community institutions.