Officially, ‘double entendre’ means a phrase that is planned with two meanings, one obvious and one subtle (the latter meaning usually being rude or otherwise risqué).
The most famous example, in the form of a joke that explains it all:
Woman walks into a bar and asks for a double entendre. So the barman gives her one.
The phrase is of French origin, so it is best pronounced as such, ‘double’ and all. Here’s our best stab at this as a phonetic form for the layman (pedants, please excuse our attempts to be accessible):
Trying to pronounce ‘double’ in English/American form (i.e. as ‘dubble’) is guaranteed to get in the way of your pronouncing ‘entendre’ correctly, and it always sounds ugly when anyone tries; you need a good run-up at the right angle to take the delicate curves of ‘entendre’, and a soft ‘doobl’ is the way to go. Pronouncing ‘double’ like ‘rubble’ sets you up to go veering off the track every time.
The plural of ‘double entendre’ is ‘double entendres’, but the ‘s’ is infuriatingly silent.
Any attempt to translate the word components of ‘double entendre’ from French into English might give you the idea that the double meaning it describes is what is heard, or understood, and not what is planned by the speaker/writer. Many subscribe to this definition no matter what any old dictionary says, probably because finding these growing in the wild is often way, way funnier than anything that might be planted deliberately, mainly because dignity comes into play. Unexpected loss of dignity is often at the root of humour in many cultures.
A famous example, allegedly spoken on live television by weightlifting commentator Pat Glenn:
“This is Gregoriava from Bulgaria… I saw her snatch this morning and it was amazing.”
So now you know what a double entendres is… or at least what most people think it should be.