Question: what is the difference between lemon curd and lemon custard?
Answer: It's a “curd” in the sense that like cheese curds, it's thickened by the action of coagulating proteins. Indeed many Brits call lemon curd lemon “cheese” for this reason. ... The main difference between curd and custard, in addition to it not having any cream or milk in it, is that it contains quite a bit more sugar.