The general definition of what constitutes a misdemeanor can be found in
California Penal Code § 17(b).
Every other crime or public offense not defined as a felony is a misdemeanor
except those offenses that are classified as infractions.
Except in cases where a different punishment is prescribed by any law of this
state, every offense declared to be a misdemeanor is punishable by
imprisonment in the county jail not exceeding six months, or by fine not
exceeding one thousand dollars ($1,000), or by both.