A subdivision is a division of land into several pieces via a parcel map or tract map.

PARCEL MAPS and CONDOMINIUM PARCEL MAPS
A parcel map is a subdivision yielding 4 or less lots based on a conditionally approved tentative map.
A condominium parcel map is a subdivision yielding 1 overall lot and condominium with 4 or less units.

TRACT MAPS and CONDOMINIUM TRACT MAPS
A tract map is a subdivision yielding 5 or more lots.
A condominium tract map is a subdivision yielding 1 overall lot and condominium with 5 or more units.

TENTATIVE MAPS
The purpose of a tentative map is to show the local government agency what exists and what is proposed on and abutting the property to be subdivided. A copy of the tentative map is submitted to the various departments (including engineering, environmental, fire, planning, recreation and parks, sanitation, street lighting, transportation, and water and power). After reviewing the proposed subdivision the departments prepare a list of conditions which must be met prior to the final approval of the subdivision.
Process:

1. A topographic survey of existing property is performed.
2. A tentative map is prepared and submitted to the local government agency for review.
3. A final map (parcel map or tract map) is prepared based on the conditions of approval by the various agency departments.