| Triangles |
| River areas |
| Some mouths |
| River parts |
| Mouth parts |
| River mouths |
| Greek letters |
| Certain stars |
| River deposits |
| River features |
| Fluvial plains |
| Mouth features |
| Mouth formations |
| Triangular areas |
| River formations |
| River mouth areas |
| River mouth parts |
| Symbols of change |
| Flood-prone areas |
| Mississippi sights |
| Triangular letters |
| Some sorority women |
| River-mouth regions |
| Triangular deposits |
| Nile and Mississippi |
| River mouth deposits |
| River mouth features |
| Some fertile regions |
| Formations at mouths |
| Areas at rivers' ends |
| River mouth landforms |
| Brackish water locales |
| River mouth formations |
| Change symbols, in math |
| Some fraternity members |
| Triangular soil deposits |
| Triangular Greek letters |
| Pointed river formations |
| Symbols of change, in math |
| The Mekong and Nile have them |
| Deposits at the mouth of a river |
| Certain Soviet nuclear submarines |
| River areas named for their shape |
| River plains named for their usual shape |