| Vast gulf |
| Wide gulf |
| Deep gulf |
| Deep gorge |
| Deep cavity |
| Yawning gulf |
| Deep, dark pit |
| Bottomless pit |
| Bottomless gulf |
| Deep-bottomed pit |
| Immeasurable void |
| Grand Canyon e.g. |
| Immeasurable cavity |
| Yawning gulf (Var.) |
| Yawning chasm (var.) |
| Wide gulf, poetically |
| Bottomless pit (var.) |
| It's immeasurably deep |
| Deep cavity, poetically |
| Vast chasm, to the Bard |
| Bottomless pit (archaic) |
| In the dark backward and ___ of time?": Shak. |