Feeding order

In phonology and historical linguistics, feeding order of phonological rules refers to a situation in which the application of a rule A creates new contexts in which a rule B can apply; it would not have been possible for rule B to apply otherwise.

Suppose there are two rules. Rule A takes in input x and returns output y. Rule B takes in input y and returns input z. When rule B is applied to input x, it will return the same output (x). The following order is called a feeding order:

1. A: x→y
2. B: y→z

The opposite of feeding order, the situation in which rule A destroys a certain context so rule B can no longer apply, is called bleeding order.