California Code, Penal Code - PEN § 553

(a) “Sign” means a sign not less than one (1) square foot in area and upon which in letters not less than two inches in height appear the words “trespassing-loitering forbidden by law,” or words describing the use of the property followed by the words “no trespassing.”

(b) “Posted property” means any property specified in Section 554 which is posted in a manner provided in Section 554.1.

(c) “Posted boundary” means a line running from sign to sign and such line need not conform to the legal boundary or legal description of any lot, parcel, or acreage of land, but only the area within the posted boundary shall constitute posted property, except as otherwise provided in subdivision (e) of Section 554.1.