State v. Munoz
In State v. Munoz, 224 Ariz. 146, 228 P.3d 138, 139 (Ariz. Ct. App. 2010) the Arizona Court of Appeals reviewed age in the context of an aggravated assault statute criminalizing an assault on a child who is fifteen "or under" by one who is at least eighteen.
In construing age, the court noted the significance of "giving words in statutes their ordinary meaning unless the context or other circumstances suggest a different meaning." Id. at 140-41.
It then consulted the definition of "age" in Black's Law Dictionary: a "period of time" or "individual existence." Id. at 141 (quoting Black's Law Dictionary 66 (8th ed. 2004)).
Black's Law Dictionary explained: "in American usage, age is stated in full years completed (so that someone fifteen years of age might actually be fifteen years and several months old)." Id.
The court noted that the common usage of "age" is referenced "in terms of years, not in months or days." Id. at 141.
The court ultimately applied the common and approved usage of the term "age" and determined "the phrase 'fifteen years of age or under'" included those who have passed their fifteenth birthday but have not yet reached their sixteenth birthday." Id. at 139.