Writing system
A writing system is any conventional system for representing a particular language using a set of symbols (called a script), as well as the rules those symbols encode. The earliest of conventional writing systems appeared during the late 4th millennium BC. Throughout history, each independently invented writing system gradually emerged from a system of proto-writing, where a small number of ideographs were used in a manner incapable of fully encoding language, and thus lacking the ability to express a broad range of ideas.