What is the difference between an abjad and an alphabet?

In a full alphabet, vowels have an equal status to consonants, whereas in an abjad, vowel marking is typically absent, partial, or optional. Conversely, abugidas use consonant units where vowel notations appear secondary like diacritics. In less formal contexts, all three writing systems may be broadly termed alphabets.

What we know

• In a full alphabet, vowels have a status equal to consonants. [2]
• In an abjad, vowel marking is absent, partial, or optional. [2]
• The Paleo-Hebrew script is an abjad consisting of 22 consonantal letters. [3]
• An abugida is a segmental writing system where vowel notation is secondary, resembling a diacritical mark. [2]

Where to go next

• the bigger pictureWhat is an abugida?
• a case in pointHow did the Ugaritic alphabet work?
• how we knowWhat are the characteristics of the Paleo-Hebrew alphabet?
• compared withHow do writing systems compare in vowel representation?
• whoWho named and classified these writing systems?
• an unexpected connectionHow does cuneiform connect to an abjad?The Ugaritic alphabet was an abjad written using cuneiform tools by pressing a wedge-shaped stylus into clay tablets.

Sources

• [1]abugida (Wikidata Q335806) · CC0 1.0
• [2]Abugida · CC BY-SA 4.0
• [3]Paleo-Hebrew alphabet · CC BY-SA 4.0
• [4]Ugaritic alphabet · CC BY-SA 4.0
• [5]Berber Latin alphabets · CC BY-SA 4.0