The seasons drawn by Nick Lomb. On Saturday 22 December 2007 at 5:08 pm Australian eastern summer time the Earth is at summer solstice. This is when the Sun appears at its most southerly position for the year and, for those of us in the southern hemisphere, it is the longest day of the year. In Sydney the Sun is above the horizon for 14 hours and 25 minutes.
Back-end systems deal with databases and data processing components, so the purpose of the back-end system is to launch the operating system's programs in response to front-end system requests and operations. In other words, the back-end system implements responses to what the front end has initiated.
Back means the opposite of front: back window. Hind, and the more formal word posterior, suggest the rearmost of two or more often similar objects: hind legs; posterior lobe. Rear is used of buildings, conveyances, etc., and in military language it is the opposite of fore: rear end of a truck; rear echelon.