sun letter

Calque of Arabic حَرْف شَمْسِيّ‎ (ḥarf šamsiyy).

sun letter (plural sun letters)

1. (linguistics) One of fourteen Arabic letters that cause the "L" of a preceding definite article اَل‎ (al-) to be assimilated in pronunciation. The sun letter suppresses the sound of the "L" and then geminates: al + ṣīn = aṣ-ṣīn. The effect of the sun letter is limited to pronunciation and does not affect the spelling, except that a shadda may be written over the sun letter and in the fully vocalised spelling lām lacks any diacritics: الصِّين‎ (aṣ-ṣīn). The fourteen sun letters are ت‎ (t), ث‎ (ṯ), د‎ (d), ذ‎ (ḏ), ر‎ (r), ز‎ (z), س‎ (s), ش‎ (š), ص‎ (ṣ), ض‎ (ḍ), ط‎ (ṭ), ظ‎ (ẓ), ل‎ (l), ن‎ (n). Phonetically, they represent coronal consonants.

• ج‎ (j) is not traditionally among the sun letters, as its corresponding sound was originally a palatal /ɟ/. However, its pronunciation in Modern Standard Arabic varies per region from /d͡ʒ/, /ʒ/, to /ɡ/, respectively both of which are coronal, and velar; prescriptively, it should still avoid assimilating the definite article in observance of tradition, but certain speakers may incorporate it as a sun letter regardless.

• solar letter

• moon letter