adj ( AmE )
( in the US education system ) relating to the years from kindergarten (= school for very young children) to 12th grade:
The state pays for a K-12 education.
K-12
Meaning of K-12 in English
Oxford guide to British and American culture English vocabulary. Руководство по британской и американской культуре, Оксфордский английский словарь. 2005