CaliforniaOpenCarry.org site asks and answers:
What is Open Carry?
Open Carry (OC) refers to the act of carrying a firearm in plain sight.
12025. (a) A person is guilty of carrying a concealed firearm when he or she does any of the following:
(1) Carries concealed within any vehicle which is under his or her control or direction any pistol, revolver, or other firearm capable of
being concealed upon the person.
(2) Carries concealed upon his or her person any pistol, revolver, or other firearm capable of being concealed upon the person.
(f) Firearms carried openly in belt holsters are not concealed within the meaning of this....