Cal. Civ. Code § 704.01

704.01 Definitions. In this chapter, unless the context indicates otherwise:
(1) “Lease” means an agreement, whether oral or written, for transfer of possession of real property, or both real and personal property, for a definite period of time. A lease is for a definite period of time if it has a fixed commencement date and a fixed expiration date or if the commencement and expiration can be ascertained by reference to some event, such as completion of a building. A lease is included within this chapter even though it may also be treated as a conveyance under ch. 706. An agreement for transfer of possession of only personal property is not a lease.
(2) “Periodic tenant” means a tenant who holds possession without a valid lease and pays rent on a periodic basis. It includes a tenant from day-to-day, week-to-week, month-to-month, year-to-year or other recurring interval of time, the period being determined by the intent of the parties under the circumstances, with the interval between rent-paying dates normally evidencing that intent.
(3) “Premises” mean the property covered by the lease, including not only the realty and fixtures, but also any personal property furnished with the realty.
(3m) “Rental agreement” means an oral or written agreement between a landlord and tenant, for the rental or lease of a specific dwelling unit or premises, in which the landlord and tenant agree on the essential terms of the tenancy, such as rent. “Rental agreement” includes a lease. “Rental agreement” does not include an agreement to enter into a rental agreement in the future.
(4) “Tenancy” includes a tenancy under a lease, a periodic tenancy or a tenancy at will.
(5) “Tenant at will” means any tenant holding with the permission of the tenant’s landlord without a valid lease and under circumstances not involving periodic payment of rent; but a person holding possession of real property under a contract of purchase or an employment contract is not a tenant under this chapter.