| Solution | Length | |
|---|---|---|
| tier | 4 | |
| mire | 4 | |
| seat | 4 | |
| sill | 4 | |
| step | 4 | |
| root | 4 | |
| seam | 4 | |
| 5 letters | ||
| story | 5 | |
| stage | 5 | |
| stuff | 5 | |
| shelf | 5 | |
| water | 5 | |
| 7 letters | ||
| radical | 7 | |
| topsoil | 7 | |
| stratum | 7 | |
| 8 letters | ||
| rudiment | 8 | |
| 9 letters | ||
| thickness | 9 | |
| substance | 9 | |
| principle | 9 | |
| underside | 9 | |
| 10 letters | ||
| UNDERLAYER | 10 | |
| UNDERNEATH | 10 | |
| underbelly | 10 | |
| 11 letters | ||
| INSTITUTION | 11 | |
| Rock bottom | 11 | |
| terra firma | 11 | |
| 12 letters | ||
| underpinning | 12 | |
| substructure | 12 | |
| 14 letters | ||
| understructure | 14 | |