The word "盾构机" is formed by combining the characters 盾 (dùn), meaning "shield", which refers to the protective structure used in tunneling; 构 (gòu), meaning "construct" or "assemble", indicating the building function; and 机 (jī), meaning "machine", specifying the device type. Together, they directly describe a machine that constructs tunnels using a shield method, hence "shield construction machine" or tunnel boring machine.