Qiyas lug'atda «o'lchash», «baholash» yoki biror narsaning uzunligi, og'irligi yoki sifatini aniqlash ma'nosini anglatadi, shuning uchun tarozilarni «miqyas» deb ataladi. Huquqshunoslik istilohi sifatida esa ko'pchilik ulamo Qiyasni quyidagicha ta'rifladi: «Hukm haqida qonunda aniq ko'rsatma bo'lmagan yangi holatga (far'), ikkala holatda ham umumiy bo'lgan sabab ('illa) tufayli, asl holatning (asl) hukmini tatbiq etish».11

The linguistic meaning of Qiyas is means estimation, measuring or ascertaining the length, weight, or quality of something, which is why scales are called miqyas. As a juristic term Qiyas the majority of Ulema have defined Qiyas as, „the application to a new case (far'), on which the law is silent, of the ruling (Hukm) of an original case (asl) because of the effective reason ('Illa) which is in common to both.‟11

Quyidagi — Qiyasning misoli:

The following is an example of Qiyas:

"Ey iymon keltirganlar! Juma kuni namozga chaqiriq eshitilganda, Allohning zikriga shoshiling va savdo-sotiqni tark eting. Bu sizlar uchun yaxshidir, agar bilsangiz. Namoz tugagach, yer yuzida tarqalib, Allohning fazlidan izlang va Allohni ko'p zikr qiling, shoyad najot topsangiz!" (TMQ al-Juma'a: 9-10)

“O you who have attained faith! When the call to prayer is sounded on the day of congregation (Friday), hasten to the remembrance of Allah, and leave all worldly commerce: this is for your own good, if you but knew it. And when the prayer is ended, disperse freely on Earth and seek to obtain Allah‟s bounty; but remember Allah often, so that you might attain to a happy state!” (TMQ al-Juma‟: 9-10)

Oyat azon-aytilganda barcha dunyoviy savdo-sotiqdan qo'l tortish kerakligini bayon qiladi. Oyatda ovqatlanish, dam olish yoki savdo-sotiqdan boshqa biror ishni to'xtatish haqida hech narsa aytilmagan. Oyatda namoz tugagach, tarqalib ketish va Allohning fazlini izlash buyurilgan. Bundan shunday xulosa kelib chiqadi: savdo-sotiqni tark etishning sababi bor, chunki agar buni qilmasak, biz o'zimizni ishga chalg'itib qo'yamiz va namozni unutib qo'yamiz.

The Ayah mentions that, when the call to prayer is given, one should disengage from all worldly commerce. The Ayah doesn‟t mention to stop such acts as eating, resting, or anything else other than conducting business. The Ayah mentions that when the prayer is over, disperse and seek Allah‟s bounty. This means that there is a reason to leave the commerce, being that if we do not, then we will be preoccupied and will forget the prayer.

Qiyos ushbu misolga ko'ra, savdodan boshqa har qanday faoliyatga ham tatbiq etiladi. Chunki juma namozini o'tkazib yuborish sababi (illat) bu faoliyatlarda ham mavjud. Shu sababli juma vaqtida ishlash, o'yin o'ynash, ovqatlanish va boshqa shunga o'xshash ishlar man etiladi, chunki bularning barchasi musulmonlarni juma namozini ado etishdan to'sadi.

The application of Qiyas for this example would be for any other activity besides commerce. This is because the „Illah (missing the Juma‟ prayer) occurs due to these activities as well. Therefore, working, playing, eating etc. are prohibited in the time of Juma‟ because all of these activities prevent Muslims from performing the Juma‟ prayer.