noun
rank insignia; badge of rank
Refers to the physical emblem or patch worn on a uniform to indicate rank, especially in military, police, or other hierarchical organizations.
彼の肩には大佐の階級章がついていた。
He had a colonel's rank insignia on his shoulder.
警察官の階級章は制服の胸や襟に付けられる。
Police officers' rank insignia are attached to the chest or collar of the uniform.
記章 is a general term for a badge or medal, often commemorative, whereas 階級章 is specifically for indicating rank.
Compound of 階級 (rank) + 章 (badge, emblem).