Why is it called nillable?

Question

In an XML schema you can mark an element as nillable meaning it can take an explicit NULL value. See nillable and minOccurs XSD element attributes for a great e

Answer 1

It comes from nil which is another term for null, used in XML. I don't think that there is any specific reason the one the be preferred over the other in different programming languages. It is just an expression. It is used in some sports too, to express 0. http://en.wikipedia.org/wiki/Nil