- of or like an abyss; immeasurable; unfathomable.
- of or relating to the biogeographic zone of the ocean bottom between the bathyal and hadal zones: from depths of approximately 13,000 to 21,000 feet (4,000 to 6,500 meters).
- of or belonging to the ocean depths, esp below 2000 metres (6500 feet)
- geology another word for plutonic
