| 1 | English | benthos | The flora and fauna at the bottom of a body of... |
| 2 | Ancient Greek | βένθος | the depths |
| 3 | Ancient Greek | βάθος | extension in space: depth, height, breadth,... |
| 4 | Ancient Greek | βαθύς | being a large vertical distance from: high, deep;... |
| 5 | Proto-Indo-European | gʷeh₂dʰ- | to sink, submerge; to tread, wade |