A writing system (also called a script) is a system of symbols used to represent language.[1][2] There are different kinds of writing systems, with symbols that represent different things. For example, English uses an alphabet (the Latin alphabet).
The fundamental principle is that symbols stand for sound, but there is more to it than that. The term "writing system" includes more than just (for example) an alphabet. Alphabets are part of a "graphic inventory" which includes punctuation, diacritics, ideograms (e.g. numbers) and logograms (standing for specific words such as $, & etc.).