俱舍論頌疏論本 1.136

1.136

釋曰：身者，體也。此六識身初謝過去，名無間滅，謂於中間無間隔故。即此六識無間滅已，為後識依，即名意界。意者，所依義故。過去識得名為意，由與現識為所依故。

The commentary says: "Body" means essence. When these six consciousness-bodies have just passed away into the past, this is called "perishing without interval" (samanantaranirodha), meaning that there is no interval in between. These very six consciousnesses, having perished without interval, serve as the basis for subsequent consciousness and are called the mind element. "Mind" has the meaning of being a basis. Past consciousness obtains the name 'mind' because it serves as the basis for present consciousness.