* Most places don't have a law specifically targeting a single absence. Laws usually address *truancy*, which is defined as habitual or excessive absences. A single absence is generally not considered truancy.
* However, schools and districts have attendance policies. Missing school without an excused absence can result in consequences from the school, such as detention, suspension, or notification of parents/guardians.
* The age of the student matters. Laws and policies are often stricter for older students who are legally required to attend school until a certain age.
* The reason for the absence matters. An excused absence (doctor's appointment, family emergency) is different from an unexcused absence.
In short, while it's unlikely to be illegal to miss a single day of school, it could result in disciplinary action from your school. Always contact the school to explain the reason for your absence.