於水得自在之禪定也。若具此定，則得使身之內外為水。猶如具火定得使依正盡為火。見水觀條。
The water dhyāna, in which one becomes identified with water, for during the period of trance one may become water; stories are told of devotees who, having turned to water, on awaking found stones in their bodies which had been thrown into their liquid bodies, and which were only removed during a succeeding similar trance.
一水定 指修習水觀而得之禪定。即一心觀想水，於水得自在，能隨意使身之內外現為水。（參閱「水觀」1953）p1946