K-12 /ˌkeɪ ˈtwelv/ BrE AmE adjective American English
connected with the part of the US education system that includes ↑ kindergarten and ↑ grade s 1–12 (ages 5–17). All education during these years is paid for by the government:
a K-12 teacher (=able to teach any level from kindergarten to 12th grade)
the K-12 curriculum