釋氏要覽 2.206

2.206

唯就法身也體依聚義。名身○攝論云。為應化身。及如來一切功德所依故。名法身也。

This refers solely to the dharmakāya. With the meaning of essence, basis, and aggregation, it is called 'body.' The Mahāyānasaṃgraha states: 'Because it is the basis for the responsive and transformative bodies and all the merits of the Tathāgata, it is called the dharmakāya.'