1. (noun) the ambiguous region between two categories or states or conditions (usually containing some features of both)

• no man's land

1. (noun) the lowest level of the ocean to which light can reach

• davy jones
• davy jones's locker
• ocean bottom
• ocean floor
• sea bottom
• sea floor
• seabed

2. (noun) the ambiguous region between two categories or states or conditions (usually containing some features of both)

• ambiguity
• equivocalness