That which, when correctly considered, leads to a Sharīʿa ruling — Qurʾān, Sunna, ijmāʿ, qiyās, and the disputed sources.

Knowledge of the practical Sharīʿa rulings derived from their detailed evidences.

A body of derived rulings and, more fundamentally, the uṣūl method that produces them — the four being Ḥanafī, Mālikī, Shāfiʿī, Ḥanbalī.

A specific question of fiqh over which a ruling is sought, often the locus of scholarly disagreement (ikhtilāf).

The root cause of a juristic disagreement — a conflict of texts, an ambiguous word, a contested qiyās, or a differing method.

The science of the principles and evidences from which the detailed rulings of the Sharīʿa are extracted, and the modes of that extraction.

The address of the Lawgiver concerning the acts of the responsible person: the five taklīfī values or the waḍʿī signs.

What is transmitted from the Prophet ﷺ of statement, act, or tacit approval — revelation alongside the Qurʾān.

The agreement of the mujtahids of the Umma in an era on a Sharīʿa ruling; qaṭʿī when of the Companions.

Departing from the apparent qiyās to a stronger consideration; admitted by Ḥanafīs and Mālikīs, rejected by Shāfiʿīs.

Proof drawn from the transmitted sources — the Qurʾān and the Sunna — as opposed to ʿaql (reason).

Attaching a case with no text to one with a text, because they share the ʿilla (effective cause) of the ruling.

Rational proof; ʿaqīda's schools differ on how far it may interpret or constrain the transmitted text (naql).

A report transmitted by numbers at every level such that their agreement upon a lie is impossible — yielding certainty (qaṭʿī).

A report not reaching tawātur; obligatory to act upon in fiqh though it yields probability (ẓann), not certainty.

As ṣaḥīḥ but with lighter precision (ḍabṭ) in a narrator; acted upon and used as evidence.

A report with a connected chain of upright, precise narrators, free of shudhūdh (irregularity) and ʿilla (hidden defect).

A narrator whose report is accepted when supported (mutābaʿa) and otherwise soft (layyin al-ḥadīth).

A narrator combining ʿadāla (uprightness) and ḍabṭ (precision) — the grade on which ṣaḥīḥ chains rest.

One lacking a condition of acceptance — deficient uprightness or precision — so his solo report is not established.

One upright but with minor lapses in precision; his solo report is typically ḥasan.

One who met the Prophet ﷺ believing in him and died upon Islam; the Companions are ʿudūl by consensus.

The mode by which a text signifies a ruling — naṣṣ (explicit) > ẓāhir (apparent) > mafhūm (implied).

The lifting of a Sharīʿa ruling by a later Sharīʿa evidence; the mansūkh (abrogated) text no longer grounds a ruling.

A proof definitive in both establishment and indication; the strongest tier, admitting no disagreement.

The position preponderant after tarjīḥ — its evidence outweighs the opposing (marjūḥ) one.

Restricting the scope of a general expression (ʿāmm) by an evidence indicating some of its instances are excluded.

Establishing the superiority of one of two conflicting evidences by a recognised factor, so it is acted upon over the other.

The mutual opposition of two evidences of equal rank; resolved by reconciliation (jamʿ), then naskh, then tarjīḥ.

The establishment of a proof-text's transmission — qaṭʿī for Qurʾān/mutawātir, ẓannī for āḥād, computed from its isnād.

The attribute the ruling is linked to and by which qiyās extends it — distinct from its ḥikma (underlying wisdom).

A proof yielding preponderant probability; the domain of legitimate ijtihād and ikhtilāf.

The position of the overwhelming majority of the mujtahids — weighty though short of ijmāʿ.

A lone view contrary to the established majority; carried little weight and not relied upon.

The body following the Prophet's Sunna and the way of the Companions in creed — encompassing the Atharī, Ashʿarī and Māturīdī schools.

A Muʿtazilī principle placing the unrepentant grave sinner in an intermediate station — a fāsiq, neither muʾmin nor kāfir.

The beatific vision of God by the believers in the Hereafter, affirmed by Ahl al-Sunna (75:22–23) and denied by the Muʿtazila.

Divine attributes established solely by the revealed text — such as al-wajh, al-yad, al-istiwāʾ — over whose interpretation the creeds most differ.

The Atharī method of affirming the revealed attributes as real, while consigning their modality (kayfiyya) to God and denying likeness to creation.

A group diverging from Ahl al-Sunna wa-l-Jamāʿa in a matter of ʿaqīda (pl. firaq) — e.g. the Muʿtazila, Khawārij, Jahmiyya.

The Ashʿarī doctrine reconciling divine creation of acts with human responsibility: God creates the deed and the servant acquires (kasaba) it, and by that acquisition is held accountable.

The question — central to the miḥna — of whether God's speech is an uncreated attribute (Ahl al-Sunna) or a created thing (Muʿtazila/Jahmiyya).

Affirming the wording of an attribute-text while entrusting its precise meaning (or modality) to God rather than interpreting it.

Affirming God's transcendence above resemblance to created things, grounded in «laysa ka-mithlihi shayʾ» (42:11).

Assimilating God's essence or attributes to those of creatures — a censured extreme opposite to taʿṭīl.

Singling out God alone in His Lordship, His right to worship, and His names and attributes; the core of ʿaqīda.

Affirming the names and attributes God affirmed for Himself, without distortion (taḥrīf), denial (taʿṭīl), asking how (takyīf) or likening to creation (tamthīl).

Affirming God's exclusive Lordship — that He alone creates, owns, sustains and governs all that exists.

Singling out God alone as the object of all worship (ʿibāda); its opposite is shirk. Also called tawḥīd al-ʿibāda.

Carrying a wording from its ẓāhir (apparent) meaning to a warranted figurative one — used by the Ashʿariyya on the ambiguous attribute-texts to uphold tanzīh.

Negating the divine attributes, wholly or in part; Ahl al-Sunna hold the Muʿtazilī denial of the ṣifāt to be taʿṭīl.

The tenets of belief affirmed with certainty as the roots of the religion (uṣūl al-dīn), as distinct from fiqh which governs action.