Al-Qiyaas is the joining of a matter to another matter within the Hukm Ash-Shar’iy due to the two matters being unified in respect to the (commonly shared) ‘Illah (reasoning) in the case where the ‘Illah represents the Baa’ith (reason/cause) for the Hukm.

Outweighing Qiyaas means outweighing a branch Hukm taken by way of Qiyaas upon another Hukm for the same branch also taken by way of another Qiyaas from another text.