light hour - the distance light travels in a vacuum in one hour; approximately one billion kilometers. 1  astronomy unit - a linear unit used for astronomical distances. 2  light year, light-year - the distance that light travels in a vacuum in 1 year; 5.88 trillion miles or 9.46 trillion kilometers.
keystone. n. 1. (Building) Also called: headstone or quoin the central stone at the top of an arch or the top stone of a dome or vault.2. something that is necessary to connect or support a number of other related things.(ËkiËstoÊn). n.eystone. n. 1. (Building) Also called: headstone or quoin the central stone at the top of an arch or the top stone of a dome or vault.
Doctrine provides a military organization with unity of effort and a common. philosophy, language, and purpose. FM 5-0 is the Armyâs keystone manual for. planning operations. It is the Armyâs doctrinal source for problem solving, the. military decision making process (MDMP), troop leading procedures (TLP), and. formats for Army plans and orders. PURPOSE. FM 5-0 promotes a common understanding of the fundamentals of planning and.