A police officer found a Swiss Army knife in a pocket of defendant Emmanuel Castillolopez's jacket. One of the blades was fully extended. Defendant was convicted of carrying a concealed dirk or dagger in violation of Penal Code section 21310. Penal Code section 16470 defines a " 'dirk' or 'dagger' ' as "a knife . . . that is capable of ready use as a stabbing weapon that may inflict great bodily injury or death." Under this definition, "a pocketknife is capable of ready use as a stabbing weapon . . . only if the blade of the knife is exposed and locked into position." (Ibid.)

The Court of Appeal reversed defendant's conviction, ruling that there was no substantial evidence that the open blade of the Swiss Army knife was "locked into position" within the meaning of Penal Code section 16470 because the knife could be closed simply by folding the blade back into the handle. We agree that defendant's conviction cannot stand and therefore affirm the judgment of the Court of Appeal.

The trouble with words is that many words have clear areas of meaning but also gray zones.  When the legislature tries to give commonly understood words precise meanings, the exercise sometimes backfires, and the precise but artificial definition can arguably include things that are obviously not within the common sense meaning of the word.

We pretty much know what a dagger is, and a Swiss Army knife is obviously not one.  Cal. Supreme had to stretch a bit to avoid including it in this case.