号令 (hàolìng): an order; a (military) command

号令 is heavyweight, formal vocabulary — military commands, imperial decrees, drill orders. Modern everyday 'orders' use 命令 mìnglìng (formal) or 吩咐 fēnfù (casual instructions from a superior). 号令 carries a whiff of grandeur: warlords 号令三军 (command the armies), but a manager 命令 the staff.

memory

号 (hào, signal / call) + 令 (lìng, order). The 号 was originally the bugle or signal flag used to issue military commands; 令 is the order itself. Together: 'signaled order.'