Sun and moon letters
distinction between two groups of Arabic consonants / From Wikipedia, the free encyclopedia
In Arabic and Maltese, consonants are divided into two groups: the sun/solar letters (Arabic: حروف شمسية ḥurūf shamsiyyah, Maltese: konsonanti xemxin) and moon/lunar letters (حروف قمرية ḥurūf qamariyyah, Maltese: konsonanti qamrin).
In those languages, all nouns start with the word "al" (الـ) in Arabic or "il" in Maltese. Both words mean "the." If a sun letter comes after the consonant, the "l" sound in "al" or "il" is dropped and is replaced by whatever sound the letter makes. However, if a moon letter comes after, the "l" sound in those words stays.
In Arabic, the word for "the sun" is ash-shams because the "sh" sound is a sun letter. Meanwhile, the word for "the moon" is al-qamar because the "q" sound is a moon letter.