An alphabet is a standard set of letters (basic written symbols or graphemes) that is used to write one or more languages based on the general principle that the letters represent phonemes (basic significant sounds) of the spoken language. This is in contrast to other types of writing systems, such as syllabaries (in which each character represents a syllable) and logographies (in which each character represents a word, morpheme, or semantic unit).
The Proto-Canaanite script, later known as the Phoenician alphabet, is the first fully phonemic script. Thus the Phoenician alphabet is considered to be the first alphabet. The Phoenician alphabet is the ancestor of most modern alphabets, including Arabic, Greek, Latin, Cyrillic, Hebrew, and possibly Brahmic. Under a terminological distinction promoted by Peter T. Daniels, an "alphabet" is a script that represents both vowels and consonants as letters equally. In this narrow sense of the word the first "true" alphabet was the Greek alphabet, which was developed on the basis of the earlier Phoenician alphabet. In other alphabetic scripts such as the original Phoenician, Hebrew or Arabic, letters predominantly or exclusively represent consonants; such a script is also called an abjad. A third type, called abugida or alphasyllabary, is one where vowels are shown by diacritics or modifications of consonantal base letters, as in Devanagari and other South Asian scripts. The Khmer alphabet (for Cambodian) is the longest, with 74 letters.