تواطؤ الفاصلتين من النثر على حرف واحد
The agreement of the ending words of two prose clauses upon one final letter.
Tawāṭuʾ means correspondence; fāṣilatayn identifies the ending words of the prose units. The phrase min al-nathr places the definition in prose, while poetry also uses the concept of rhyme, qāfiyah.
Equality of every word’s metrical or morphological pattern is not required by this general definition. Agreement at the ending is central, though the patterns and lengths of the two units may differ.