What is white coffee? What is white coffee? 

Does "white coffee" refer to the roast level of the beans, or additives to the beverage, or is it some other type of coffee bean, or a different beverage completely?
As suggested by several previous comments, there's several things that could be called "white coffee." 

According to the white coffee article on Wikipedia, and other sources (e.g., coffeefaq, Nescafé); others listed below.


Simply referring to coffee with whitener (e.g., milk, creamer, etc.);
A Lebanese drink ahweh bayda, made from water, orange blossom water, and (perhaps) sugar (more here)
Something called Ipoh white coffee; of Malaysian origin, this refers to beans that are lightly roasted with margarine (and perhaps sugar and wheat), brewed and served with sweetened condensed milk.
Coffee beans that are roasted to the "yellow" roast level, then ground and prepared as espresso; the result is a pale yellow brew with a nutty flavour and assertive acidity.
A beverage originating in Yemen, probably from the literal translation qahwa bayda. I've never had this, and can't find consistent information on it, but things that I have seen suggest that it's any number of different preparations, including the following: coffee made from lightly roasted beans plus spices; or a spiced coffee cherry tea (e.g., qishr); or even something non-coffee similar to the Lebanese variety above.
A longer shot (so to speak...) is that it could indicate a flat white, which is a coffee drink similar to a cappuccino or latte but with higher proportion of milk.
There is also a company called White Coffee Corporation, but perhpas not what you're looking for.


I hope this is a reasonable (albeit, perhaps not acutely helpful) summary.