FromProto-Celtic*brawū(“millstone”), fromProto-Indo-European*gʷréh₂wō(“heavy stone”), from*gʷréh₂us(“heavy”).
Not attested in the plural until Middle Irish
| singular | dual | plural | |
|---|---|---|---|
| nominative | brao,bráu,broo | — | — |
| vocative | brao,bráu,broo | — | — |
| accusative | *broïnN | — | — |
| genitive | broon | — | — |
| dative | *broïnL,braoL | — | — |
| radical | lenition | nasalization |
|---|---|---|
| brao | brao pronounced with/β(ʲ)-/ | mbrao |
Note: Certain mutated forms of some words can never occur in Old Irish.
All possible mutated forms are displayed for convenience.