Matres lectionis (from Latin "mothers of reading", singular form: mater lectionis, from Hebrew: אֵם קְרִיאָה‎ ʾem kəriʾa) are consonants that are used to indicate a vowel, primarily in the writing down of Semitic languages such as Arabic, Hebrew and Syriac. The letters that do this in Hebrew are aleph א‎, he ה‎, waw ו‎ and yod י‎, and in Arabic, the matres lectionis (though they are much less often referred to thus) are ʾalif ا‎, wāw و‎ and yāʾ ي‎. The 'yod and waw in particular are more often vowels than they are consonants.