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.
What is MAXIM? An established principle or proposition. A principle of law universally admitted, as being a correct statement of the law, or as agreeable to natural reason. Coke defines a maxim to be âconclusion of reason,â and says that it is so called âquia maxima ejus dignitas et certissima auctorir tas, et quod maxime omnibus probetur.â Co. Litt. llo.