Grammar term · Nahw · syntax
عَطْف بَيَان
'atf bayan

Explanatory apposition

Nahw · syntaxSyntactic roleadvanced term41+ in the Qur'an
In one line
Explanatory apposition — a second, clearer name for the same thing, agreeing in case.
Classical definition
عَطْفُ البَيَانِ تَابِعٌ جَامِدٌ يُشْبِهُ النَّعْتَ فِي إِيضَاحِ مَتْبُوعِهِ أَوْ تَخْصِيصِهِ.
“Atf al-bayan is a rigid (non-derived) follower which, like the adjective, clarifies or specifies the word it follows.”
(بتصرف من الألفية)
Key words in the Arabic
جَامِدrigid — not derived from a root pattern
إِيضَاحclarifying
تَخْصِيصspecifying
Understand it

Sometimes a name needs a clearer name beside it: أَبُو حَفْصٍ عُمَرُ — “Abu Hafs, (that is,) Umar”. The second noun explains the first, matching its case, like an adjective that happens to be a noun. It differs from badal mainly in intent: bayan re-labels to clarify; badal re-states to substitute.

How to spot it
Recognition test
Two names for one referent side by side, second clarifying the first, cases matching — atf bayan.
Related terms
Domain: Nahw · Category: Syntactic role · Frequency in the Qur'an: 41 · Source: بتصرف من الألفية, cross-checked against the Quranic corpus · Reviewed by Ustad M. Arjan Ali