俱舍論頌疏論本 1.125

1.125

四餘名行蘊者，明行蘊也。四者，謂色、受、想、識。除四蘊外，諸餘心所有四十四，及十四不相應，此五十八法是四蘊餘，總名行蘊。造作、遷流二義名行。據此義邊，色等五蘊俱合名行，謂由行蘊攝法多故，偏得行名。

"The remaining four are the aggregate of formations" clarifies the aggregate of formations (saṃskāra-skandha). "Four" refers to matter, sensation, conception, and consciousness. Excluding these four aggregates, all the remaining mental factors are forty-four in number, along with the fourteen non-concurrent [formations]. These fifty-eight dharmas are the remainder of the four aggregates and are collectively named the aggregate of formations. The two meanings of fabricating and flowing onward are named 'formations'. In light of this meaning, all five aggregates, matter and the rest, ought equally to be named formations; but because the aggregate of formations subsumes the greatest number of dharmas, it uniquely obtains the name 'formations'.