This condition of reality is perceived in fifth level of apprehension of the principle of Consciousness-only. The apprehension of perfectly accomplished reality. Objects which are arisen from true seeds, have true substance and function, and which the mind cognizes in their true aspect. The objective aspect as objectified by the first five objects and the five organs, or the objective aspect of the mind fixed in concentration. The world of original essence.
Ocean is a metaphor for great depth and breadth.
Nature refers to that which is unchanging, whether in the station of Buddhahood or sentient being. Another name for the M dhyamika school. The original nature of things manifest just as it is. The appearance of the reality-nature.