II. ĭ-Stems.
A. Masculine and Feminine ĭ-Stems.
[37]. These regularly end in -is in the Nominative Singular, and always have -ium in the Genitive Plural. Originally the Accusative Singular ended in -im, the Ablative Singular in -ī, and the Accusative Plural in -īs; but these endings have been largely displaced by -em, -e, and -ēs, the endings of Consonant-Stems.
[38].
| Tussis, f., cough; stem, tussi-. | Īgnis, m., fire; stem, īgni-. | Hostis, c., enemy; stem, hosti-. | ||
SINGULAR. | TERMINATION. | |||
| Nom. | tussis | īgnis | hostis | -is |
| Gen. | tussis | īgnis | hostis | -is |
| Dat. | tussī | īgnī | hostī | -ī |
| Acc. | tussim | īgnem | hostem | -im, -em |
| Voc. | tussis | īgnis | hostis | -is |
| Abl. | tussī | īgnī or e | hoste | -ī, -e |
PLURAL. | ||||
| Nom. | tussēs | īgnēs | hostēs | -ēs |
| Gen. | tussium | īgnium | hostium | -ium |
| Dat. | tussibus | īgnibus | hostibus | -ibus |
| Acc. | tussīs or -ēs | īgnīs or -ēs | hostīs or -ēs | -īs, -ēs |
| Voc. | tussēs | īgnēs | hostēs | -ēs |
| Abl. | tussibus | īgnibus | hostibus | -ibus |
1. To the same class belong—
| apis, bee. | crātis, hurdle. | †*secūris, axe. |
| auris, ear. | *febris, fever. | sēmentis, sowing. |
| avis, bird. | orbis, circle. | †*sitis, thirst. |
| axis, axle. | ovis, sheep. | torris, brand. |
| *būris, plough-beam. | pelvis, basin. | †*turris, tower. |
| clāvis, key. | puppis, stern. | trudis, pole. |
| collis, hill. | restis, rope. | vectis, lever. |
| and many others. |
Words marked with a star regularly have Acc. -im; those marked with a † regularly have Abl. -ī. Of the others, many at times show -im and -ī. Town and river names in -is regularly have -im, -ī.
2. Not all nouns in -is are ĭ-Stems. Some are genuine consonant-stems, and have the regular consonant terminations throughout, notably, canis, dog; juvenis, youth.[[14]]
3. Some genuine ĭ-Stems have become disguised in the Nominative Singular; as, pars, part, for par(ti)s; anas, duck, for ana(ti)s; so also mors, death; dōs, dowry; nox, night; sors, lot; mēns, mind; ars, art; gēns, tribe; and some others.