(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.