Lock-step. A mode of marching by a body of men going one after another as closely as possible, in which the leg of each moves at the same time with and closely follows the corresponding leg of the person directly before him. [Thomas Wilhelm, "Military Dictionary and Gazetteer," Philadelphia, 1881]
Figurative use by 1836. In the Hebrew Bible there are nine different names for the insect or for particular species or varieties; in the English Bible they are rendered sometimes 'locust,' sometimes 'beetle,' 'grasshopper,' 'caterpillar,' 'palmerworm,' etc. The precise application of several names is unknown. [OED]