A white lie is not a lie at all. It is where you tell the truth but you do not tell all of the truth. This means that everything you say is a white lie because when someone says, for example, "What do you want to do today?" you say, "I want to do painting with Mrs. Peters," but you don't say, "I want to have my lunch and I want to go to the toilet and I want to go home after school and I want to play with Toby and I want to have my supper and I want to play on my computer and I want to go to bed."
Mark Haddon: The curious incident of the dog in the night-time