secret sauce

Noun

 * 1) A sauce used in cooking or as a condiment, the ingredients of which are kept secret.
 * 2)  A secret idea or plan; a crucial element of something that makes it unique or functional.
 * 1)  A secret idea or plan; a crucial element of something that makes it unique or functional.
 * 1)  A secret idea or plan; a crucial element of something that makes it unique or functional.
 * 1)  A secret idea or plan; a crucial element of something that makes it unique or functional.
 * 1)  A secret idea or plan; a crucial element of something that makes it unique or functional.
 * 1)  A secret idea or plan; a crucial element of something that makes it unique or functional.