Hand (unit) radix numbering system, where a hand is four inches. The hand, sometimes also called a handbreadth or handsbreadth, is an anthropic unit, originally based on the breadth of a male human hand, either with or without the thumb, or on the height of a clenched fist. On surviving Ancient Egyptian cubit-rods, the royal cubit is divided into seven palms of four digits or fingers each. Five digits are equal to a hand, with thumb; and six to a closed fist. The royal cubit measured approximately 525 mm, so the length of the ancient Egyptian hand was about 94 mm. In
A unit A unit An A unit, in railroad terminology, is a diesel locomotive (or more rarely an electric locomotive) equipped with a driving cab and a control system to control other locomotives in a multiple unit, and therefore able to be the lead unit in a consist of several locomotives controlled from a single position. This terminology is generally used in North America, since only there was it commonplace to build B units—cabless locomotive units which normally could not lead a train. Typical driving cab features, and therefore A unit features, include windshields, rectangular side windows, crew seats, heating, and sometimes,