Arabic definite article
In Arabic and Maltese, the consonants are divided into two groups, called the sun letters or solar letters ( ', Maltese: "konsonanti xemxin") and moon letters or lunar letters (Arabic: ', Maltese: "konsonanti qamrin"), based on whether they assimilate the letter ' ( ') of a preceding Arabic definite article "al-" (), which is an important general rule used in Arabic grammar. Phonetically, sun letters are ones pronounced as coronal consonants, and moon letters are ones pronounced as other consonants.