5. Nouns ending in y in the singular, with no other vowel in the same syllable, change it into ies in the plural; as, beauty, beauties; fly, flies. But the y is not changed, where there is another vowel in the syllable; as, key, keys; delay, delays; attorney, attorneys; valley, valleys; chimney, chimneys.
6. Mathematics, metaphysics, politics, optics, ethics, pneumatics, hydraulics, &c. are construed either as singular or plural nouns.
7. The word news is always singular. The nouns means, alms, and amends, though plural in form, may be either singular or plural in signification. Antipodes, credenda, literati, and minutiæ are always plural. Bandit is now used as the singular of Banditti.
8. The following nouns form their plurals not according to any general rule; thus, man, men; woman, women; child, children; ox, oxen; tooth, teeth; goose, geese; foot, feet; mouse, mice; louse, lice; brother, brothers or brethren; cow, cows or kine; penny, pence, or pennies when the coin is meant; die, dice for play, dies for coining; pea and fish, pease and fish when the species is meant, but peas and fishes when we refer to the number; as, six peas, ten fishes.
9. The following compounds form their plurals thus: handful, handfuls; cupful, cupfuls; spoonful, spoonfuls:—brother-in-law, brothers-in-law; court-martial, courts-martial.
The following words form their plurals according to the rules of the languages from which they are adopted.
| Singular | Plural. |
| Antithesis | antitheses |
| Apex | apices |
| Appendix | {appendixes or |
| {appendices | |
| Arcanum | arcana |
| Automaton | automata |
| Axis | axes |
| Basis | bases |
| Beau | {beaux or |
| {beaus | |
| Calx | {calces or |
| {calxes | |
| Cherub | {cherubim or |
| {cherubs | |
| Crisis | crises |
| Criterion | criteria |
| Datum | data |
| Diæresis | diæreses |
| Desideratum | desiderata |
| Effluvium | effluvia |
| Ellipsis | ellipses |
| Emphasis | emphases |
| Encomium | {encomia or |
| {encomiums | |
| Erratum | errata |
| Genius | genii [2] |
| Genus | genera |
| Hypothesis | hypotheses |
| Ignis fatuus | ignes fatui |
| Index | {indices or |
| {indexes[3] | |
| Lamina | laminae |
| Magus | magi |
| Memorandum | {memoranda or |
| {memorandums | |
| Metamorphosis | metamorphoses |
| Parenthesis | parentheses |
| Phenomenon | phenomena |
| Radius | {radii or |
| {radiuses | |
| Stamen | stamina |
| Seraph | {seraphim or |
| {seraphs | |
| Stimulus | stimuli |
| Stratum | strata |
| Thesis | theses |
| Vertex | vertices |
| Vortex | {vortices or |
| {vortexes |
CASE.
Case, when applied to nouns and pronouns, means the different state, situation, or position they have in relation to other words. Nouns have three cases, the nominative, the possessive, and the objective.
I deem the essential qualities of case, in English, to consist, not in the changes or inflections produced on nouns and pronouns, but in the various offices which they perform in a sentence, by assuming different positions in regard to other words. In accordance with this definition, these cases can be easily explained on reasoning principles, founded in the nature of things.