noun
marching in file
Refers to a formation where people march in a single file or column, often used in military or ceremonial contexts.
兵士たちは分列行進で広場を横切った。
The soldiers crossed the square marching in file.
Compound of 分列 (bunretsu, 'filing, forming a line') and 行進 (kōshin, 'march, parade').