NOUNS ENDING IN O.
Errors sometimes occur in forming the plural of nouns in o. We frequently see frescoes, mottos,—both wrong. The general rule is, If the final o has a vowel before it, form the plural by adding s: as “cameo, cameos”; if a consonant precede the final o, add es; as “archipelago, archipelagoes.” Such exceptions to the general rule as are most frequently met with, and a few that are rare, we here subjoin: {p168}
| Albino | Albinos |
| Armadillo | Armadillos |
| Busto | Bustos |
| Canto | Cantos |
| Catso | Catsos |
| Cento | Centos |
| Dido | Didos |
| Domino | Dominos |
| Duo | Duos |
| Duodecimo | Duodecimos |
| Embryo | Embryos |
| Exaltado | Exaltados |
| Folio | Folios |
| Fresco | Frescos |
| Gaucho | Gauchos |
| Grotto | Grottos |
| Halo | Halos |
| Inamorato | Inamoratos |
| Internuncio | Internuncios |
| Junto | Juntos |
| Lasso | Lassos |
| Limbo | Limbos |
| Memento | Mementos |
| Merino | Merinos |
| Mestizo | Mestizos |
| Nuncio | Nuncios |
| Octavo | Octavos |
| Octodecimo | Octodecimos |
| Piano | Pianos |
| Portico | Porticoes, Wb. or Porticos, Wor. |
| Portfolio | Portfolios |
| Proviso | Provisos |
| Punctilio | Punctilios |
| Quarto | Quartos |
| Rotundo | Rotundos |
| Salvo | Salvos |
| Sextodecimo | Sextodecimos |
| Sirocco | Siroccos |
| Solo | Solos |
| Trio | Trios |
| Two | Twos |
| Tyro | Tyros |
| Virtuoso | Virtuosos |
| Zero | Zeros |
But “albugo” has pl. “albugines”; and to “imago” we should probably have to write pl. “imagines.” There are many nouns ending in o, for whose plurals we have not found any authority beyond the general rule. With the exceptions given above, the rule may be safely followed. The plural of “portico” is a matter of style: and there is some authority for “quartoes.”