Words where the singular termination -on is changed in the plural into -a:—
| Sing. | Plur. | Sing. | Plur. |
| Aphelion | aphelia | Criterion | criteria |
| Perihelion | perihelia | Ephemeron | ephemera |
| Automaton | automata | Phænomenon | phænomena. |
SECOND CLASS.
Words where the plural is formed from the original root by adding either -es or -a, but where the singular rejects the last letter of the original root.
| Plurals in -es:— | ||
| Original root. | Plur. | Sing. |
| Apsid- | apsides | apsis |
| Cantharid- | cantharides | cantharis |
| Chrysalid- | chrysalides | chrysalis |
| Ephemerid- | ephemerides | ephemeris |
| Tripod- | tripodes | tripos. |
| Plurals in -a:— | ||
| Original root. | Plur. | Sing. |
| Dogmat- | dogmata | dogma |
| Lemmat- | lemmata | lemma |
| Miasmat- | miasmata | miasma.[[34]] |
[§ 83]. Miscellaneous elements.—Of miscellaneous elements we have two sorts; those that are incorporated in our language, and are currently understood (e.g., the Spanish word sherry, the Arabic word alkali, and the Persian word turban), and those that, even amongst the educated, are considered strangers. Of this latter kind
(amongst many others) are the oriental words hummum, kaftan, gul, &c.
Of the currently understood miscellaneous elements of the English language, the most important are from the French; some of which agree with those of the Latin of the fourth period, and the Greek, in preserving the French plural forms—as beau, beaux, billets-doux.
Italian.—Some words of Italian origin do the same; as virtuoso, virtuosi.
Hebrew.—The Hebrew words, cherub and seraph do the same; the form cherub-im, and seraph-im being not only plurals but Hebrew plurals.