The following words and phrases when used in this chapter shall have the meanings given to them in this section unless the context clearly indicates otherwise:
"Adult." An individual who is at least 21 years of age.
"Ignition interlock system." A system approved by the department which prevents a vehicle from being started or operated unless the operator first provides a breath sample indicating that the operator has an alcohol level less than 0.025%.
"Minor." An individual who is under 21 years of age.