동시simultaneousness; concurrence 공동collaboration 공동생활communal life 공동적being common 공동체community 동the 동갑same age 동기sibling 동기same period 동기간sibling relationship

초급elementary level; beginning stage 초급반beginner's class 최고급the highest grade; top-level 특급special class; special rank; special grade 하급생junior student; underclassman 고급high quality; high grade 고급반class for advanced learners; the highest-level class 고급품high-end product 고급화enhancement 상급반upper grades; higher grades