Saboda haka ma'anar usūl al-fiqh shi ne ka'idoji (qawā'id) waɗanda ta hanyarsu ake samun ƙwarewa wajen fahimtar hukunce-hukuncen aiki da aka samo daga hujjoji na tafsili.
Don haka, usūl al-fiqh a ƙa'ida ana bayyana shi da cewa: ilimin ƙa'idojin da ta hanyarsu ake fitar da hukunce-hukuncen shari'a daga hujjoji na tafsili. Waɗannan ƙa'idoji kansu ana kiransu usūl al-fiqh. Littafin usūl al-fiqh kuwa littafi ne da ya ƙunshi waɗannan ƙa'idoji.
Nazarin usūl al-fiqh nazari ne na ƙa'idoji da hujjoji, wato na hukunci, tushen hukuncin, da hanyar fitar da hukuncin daga waɗannan tushe. Usūl al-fiqh ya ƙunshi hujjoji na gaba ɗaya (adillah ijmāliyyah) da yadda suke nuna hukunce-hukuncen shari'a, kuma ya ƙunshi, gabaɗaya, halin wanda yake yin istidlali (mustadil), wato ilimin ijtihādi. Haka kuma ya ƙunshi hanyar fitar da hukunci: auna (ta'ādul) da bada fifiko (tarjīh) tsakanin hujjoji. Hakika ijtihādi da tarjīh sun dogara ne da sanin hujjoji da yadda suke nuna hukunce-hukunce. Saboda haka hujjoji da yadda suke nuna hukunce-hukunce su ne ginshiƙai biyu na usūl al-fiqh, tare da nazarin hukuncin kansa da abubuwan da suka danganci shi.
Therefore the meaning of usūl al-fiqh is the principles [qawā’id] upon which the acquisition of the mastery of the practical rules (derived) from the detailed evidences is built. Hence usūl al-fiqh is defined conventionally as the knowledge of the principles whereby the derivation [istinbāt] of the shar’i rulings from the detailed evidences is attained; and these principles themselves are also termed usūl al-fiqh. A book of usūl al fiqh is a book which contains these principles. The study of usūl al-fiqh is a study of the principles and of the evidences, that is, of the ruling [hukm], the sources of the ruling, and the methodology of deriving the ruling from these sources. Usūl al-fiqh includes the general evidences [adillah ijmāliyyah] and the ways in which these indicate upon the shar’i rules, as it includes, generally, the state of the one doing the deduction [mustadil]; that is, (it includes) the knowledge of ijtihād. It also includes the methodology of derivation: weighing [ta’ādul] and giving preference [tarjīh] between evidences. Indeed, ijtihād and tarjīh depend upon knowledge of the evidences and the ways in which these indicate upon the rulings. Therefore the evidences and the way in which they indicate upon the rulings are the two foundations of usūl al-fiqh, together with the study of the ruling itself and matters related to it.
Saboda haka usūl al-fiqh shi ne dalilai gabaɗaya marasa ƙayyadaddun ma'ana na fiqh, kamar umarni mara iyaka [mutlaq al-‘amr], hani mara iyaka [mutlaq al-nahy], aikin Manzon Allah ﷺ, ijma'in sahabbai, da qiyas. Wannan ya fitar da dalilai ƙayyadaddun bayani, kamar "Ku tsayar da salla", "Kada ku kusanci zina", sallar Manzon Allah ﷺ a cikin Ka'aba, kafa wilāyah ga wanda ba zai iya kula da al'amuransa ba [mahjūr], da cancantar wakili ga albashi idan aka ɗauke shi aiki bisa biyan kuɗi, bisa qiyas da ma'aikaci. Duk waɗannan ba sashe ne na usūl al-fiqh ba, domin dalilai ne ƙayyadaddun bayani. Kasancewar an same su ana amfani da su a matsayin misali a nazarin usūl al-fiqh ba ya nufin cewa su sashe ne na shi. A'a, usūl al-fiqh shi ne dalilai gabaɗaya, da hanyar da waɗannan dalilai ke nuni (zuwa ga hukunci), da yanayin wanda ke ba da dalili, da hanyar istidlāl (neman dalili).
Thus usūl al-fiqh is the unspecified general indications for fiqh, like the absolute command [mutlaq al-‘amr], absolute prohibition [mutlaq al-nahy], the action of the Prophet (saw), ijma’ al-sahaba and qiyas. This excludes the detailed specific indications like “Establish prayer”, “And do not come near fornication”, the prayer of the Messenger (saw) inside the Ka’bah, the establishment of guardianship [wilāyah] over the one incapable of looking after his own affairs [mahjūr], the deserving of the representative to wages when hired on the basis of payment on analogy to an employee. All these are not part of usūl al-fiqh because they are specific detailed evidences. Finding them used as examples in the study of usūl al-fiqh does not mean they are a part of it. Nay, usūl al fiqh is the general evidences, the way in which these indicate (upon the ruling), the state of the one evidencing, and the methodology of evidencing [istidlāl].
Usūl al-fiqh yatsaya da fiqh a cikin cewa maudū'in fiqh shi ne ayyukan bayi dangane da halaccinsu, haramcinsu, ingancinsu, rashin ingancinsu da bata-ba (rashin hukuncinsu). Amma usūl al-fiqh, maudū'insa shi ne dalilan rubutu dangane da shari'a ahkām da ake fitar da su daga gare su, wato dangane da yadda suke kafa shari'a ahkām. Saboda haka wajibi ne (wajen nazarin usūl al-fiqh) a yi nazarin hukunci da abin da ke da alaƙa da shi dangane da bayanin wanda ke ba da hukuncin, wato, wanda yake da ikon ba da hukunci: shi ne mai shari'a, da kuma dangane da wanda hukuncin ya shafa, wato, wanda ke da alhakin aiwatar da hukuncin, ma'ana, wanda hukuncin ya wajaba a kansa [mahkūm 'alayh], da kuma dangane da hukuncin kansa: menene shi, kuma menene hakikaninsa? Bayan haka sai bayanin dalilai da hanyoyin da suke nuna hukuncin.
Usūl al-fiqh differs from fiqh in that the subject of fiqh is the actions of the servants with regards to them being permissible, prohibited, valid, invalid and void. As for usūl al fiqh, its subject is the textual evidences with regards to the shar’i ahkām being derived from them, that is, with regards to how they establish the shar’i ahkām. Thus it is necessary (in studying usūl al-fiqh) to study the hukm and that which is related to it with regards to the explanation of who is it that issues the hukm, that is, who has the right to issue the hukm: who is the legislator, and with regards to upon whom does the hukm apply, that is, who is responsible for executing the hukm, meaning, the one upon whom the hukm is obligated [mahkūm ‘alayh], and with regards to the hukm itself: what is it, and what is its reality? After this comes the explanation of the evidences and the ways in which they indicate upon the ruling