en‧tre nous /ˌɒntrə ˈnuː $ ˌɑːn-/
adverb British English spoken[
Date: 1600-1700;
Language: French;
Origin: 'between ourselves']
used humorously to tell someone that what you are going to say is secret and they must not tell anyone else
[TahlilGaran] Dictionary of Contemporary English ▲