An abugida (/ˌɑːbuːˈɡiːdə, ˌæb-/ ; from Geʽez: አቡጊዳ, 'äbugīda)—sometimes also called an alphasyllabary, neosyllabary, or pseudo-alphabet—is a segmental writing system in which consonant–vowel sequences are written as units; each unit is based on a consonant letter, and vowel notation is secondary, like a diacritical mark. This contrasts with a full alphabet, in which vowels have status equal to consonants, and with an abjad, in which vowel marking is absent, partial, or optional. In less formal contexts, all three types of script may be termed "alphabets". The terms also contrast them with a syllabary, in which a single symbol denotes the combination of a consonant and a vowel.
Related concepts were introduced independently in 1948 by James Germain Février (using the term néosyllabisme) and David Diringer (using the term semisyllabary), and in 1959 by Fred Householder (introducing the term pseudo-alphabet). The Ethiopic term "abugida" was chosen as a designation for the concept in 1990 by Peter T. Daniels. Faber suggested "segmentally coded syllabically linear phonographic script"; William O. Bright used the term alphasyllabary; and Gnanadesikan and Rimzhim, Katz, & Fowler suggested aksara or āksharik.