From Coastal Wiki
Definition of Surf zone or Breaker zone:
The surf zone (or breaker zone) is the zone where waves break as a consequence of depth limitation and surf onshore as wave bores.
This is the common definition for Surf zone or Breaker zone, other definitions can be discussed in the article
The width of the surf zone varies depending on the wave conditions and water level. The surf zone is narrow and close to the shoreline in a gentle wave climate and can be very wide under storm conditions, extending from the seaward boundary of the upper shoreface to the dunefoot. It is estimated that 80 to 90% of the yearly littoral transport takes place within the breaker or surf zone.