Linked from
The 23 pages that link to Alphabet, each with the reason it gives.
AbjadCompared with: Unlike an abjad, an alphabet normally gives vowels full letter status.
SyllabaryCompared with: Alphabets encode smaller sound units than syllabaries.
Khmer scriptCompared with: Unlike an alphabet, Khmer consonant letters carry inherent vowels.
Proto-writingCompared with: An alphabet encodes pronunciation systematically, unlike proto-writing.