An abugida, also called an alphasyllabary, is a writing system wherein the basic symbols represent a consonant plus an unmarked vowel. When a different vowel is wanted, a diacritic or some other modification is made to the sign. The sign used to indicate the vowel is dropped is called a virama, or a "vowel killer".
The word "abugida" comes from the first few signs of the Ethiopic Amharic script, which is an example of an abugida. Devanagari is another abugida, used in India.