A Cambridge change is a philosophical concept of change according to which an entity x has changed if, and only if there is some predicate F that is true (not true) of x at a time t1 but not true (true) of x at some later time t2.
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History
The term Cambridge change was coined by Peter Geach in the late 1960s, in reference to Russell and McTaggart, philosophers active at Cambridge University.
Example
Suppose that at t1, person A is 180 cm tall and person B is 175 cm tall, while at time t2 A is still 180 cm tall but B has grown to be 185 cm tall. Since the predicate `is taller than B' is true of A at t1 but not true of A at t2, A has changed according to the Cambridge change definition of "change"---he has gone from being taller than B to not being taller than B.
Intuitively, however, it is only person B, and not person A, who has changed: B has grown by 10 cm, but A has stayed the same. This problem with Cambridge changes is usually thought to call for a distinction between intrinsic and extrinsic, or natural and non-natural, properties. Given such a distinction, it is possible to define "real" change by requiring that the predicate involved express an intrinsic property, like being 175 cm tall, rather than an extrinsic property, like being taller than B.