What is "mater lectionis"

n. (context phonology English) A consonant letter used to represent a vowel sound in Semitic scripts.

In the spelling of Hebrew and some other Semitic languages, matres lectionis (; from Latin "mothers of reading", singular form: mater lectionis, ), refers to the use of certain consonants to indicate a vowel. The letters that do this in Hebrew are aleph, he, waw (or vav) and yod (or yud). The yod and waw in particular are more often vowels than they are consonants. In Arabic, the matres lectionis (though they are much less often referred to thus) are alif ا, waw و, and ya' ي.