Benthos

Benthos was a Delta Quadrant location associated with the Benthans.

Engineers on Benthos worked on a coaxial warp drive. (VOY: "Vis à Vis")

This location was only mentioned in dialogue.
The Steth impostor claimed to be from the fourth planet of the Benthan system, and at one point told a story about having to limp back to Benthos, suggesting that Benthos was the name of that planet. However, later the real Steth took back the impostor entity to Bentha. How these three locations inter-relate is unknown.
According to the Star Trek: Star Charts (p. 89), Benthos, also known as Bentha, was a star system. The primary of this system was a K-class star. In accordance with a naming scheme common to Star Trek, where a planet could share its name with its primary, there might be a planet named Benthos in this system.

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