Summary
Catchment areas and distance rules are related, but they are not the same. A catchment area is a defined priority area used by some admission authorities. A distance rule ranks applicants by how far they live from the school, using the measurement method stated in the admission policy.
For buyers, the danger is assuming that being inside a catchment or living nearby guarantees a place. It usually does not. The school may be oversubscribed, sibling priority may rank ahead of distance, faith or aptitude criteria may apply, and the measured distance may be straight line or walking route from specific address and school points. Always check the current admission arrangements and, where available, last distance offered data.
Definition
A catchment area is a defined geographic priority area used in some admissions policies. A distance rule is an oversubscription criterion or tie break that ranks applicants by measured distance between home and school according to the method set in the policy.