“Ade” is a generic term for a fruit-flavoured sweet drink.
The fruit flavour is usually citrus — as in Lemonade or Orangeade — but not necessarily always so. There are, for example, recipes for “cherryade.” Fruit flavours can even be mixed. The drinks are non-alcoholic, but that doesn’t preclude space in the glass being reserved for a glug of gin or vodka.
As far as the FAO (United Nation’s Food and Agriculture Organization) is concerned, the definition of an “Ade” drink is 10% or greater fruit juice, sugar and water. In America, however, there is no legal requirement about the use of “Ade” in the name of a commercial drink.
Typically in an “Ade” drink, there is only either a very small amount of fruit juice, or all the flavouring is artificial.
“Ade” style drinks are perfect for juice from lemons and limes which would be too strong and sour to drink on their own without sweetening. In lemonade, you generally can’t go much higher than 10 to 15% actual juice, or so much sugar would be required to counteract the sourness that your teeth would rot on the spot.
Kool-Aid’s name is based on “Ade”, reflecting the fruit flavours it comes in.
Other commercial “Ade” drinks currently (2007) being sold include Gatorade and Powerade.
For Hallowe’en punches, there is even a “Ghoul-Ade” recipe.