| 1 | Latin | Mercius | — |
| 2 | Old English | Mierce | — |
| 3 | Old English | mearc | mark, sign, character; boundary, limit |
| 4 | Proto-West Germanic | marku | boundary, border |
| 5 | Proto-Germanic | markō | border, boundary; region, area |
| 6 | Proto-Indo-European | morǵ- | edge, boundary, border; frontier, border |