[231.] Nouns of the Third Declension. The third declension is called the Consonant or I-Declension, and its nouns are classified according to the way the stem ends. If the last letter of the stem is a consonant, the word is said to have a consonant stem; if the stem ends in -i-, the word is said to have an i-stem. In consonant stems the stem is the same as the base. In i-stems the stem is formed by adding -i- to the base. The presence of the i makes a difference in certain of the cases, so the distinction is a very important one.
[232.] Consonant stems are divided into two classes:
I. Stems that add -s to the base to form the nominative singular.
II. Stems that add no termination in the nominative singular.
CLASS I
[233.] Stems that add -s to the base in the nominative singular are either masculine or feminine and are declined as follows:
| prīnceps, m., chief | mīles, m., soldier | lapis, m., stone | ||
| Bases or Stems | prīncip- | mīlit- | lapid- | |
| Singular | TERMINATIONS M. AND F. | |||
|---|---|---|---|---|
| Nom. | prīnceps | mīles | lapis | -s |
| Gen. | prīn´cipis | mīlitis | lapidis | -is |
| Dat. | prīn´cipī | mīlitī | lapidī | -ī |
| Acc. | prīn´cipem | mīlitem | lapidem | -em |
| Abl. | prīn´cipe | mīlite | lapide | -e |
| Plural | ||||
| Nom. | prīn´cipēs | mīlitēs | lapidēs | -ēs |
| Gen. | prīn´cipum | mīlitum | lapidum | -um |
| Dat. | prīnci´pibus | mīlitibus | lapidibus | -ibus |
| Acc. | prīn´cipēs | mīlitēs | lapidēs | -ēs |
| Abl. | prīnci´pibus | mīlitibus | lapidibus | -ibus |
| | ||||
| rēx, m., king | iūdex, m., judge | virtūs, f., manliness | ||
| Bases or Stems | rēg- | iūdic- | virtūt- | |
| Nom. | rēx | iūdex | virtūs | -s |
| Gen. | rēgis | iūdicis | virtū´tis | -is |
| Dat. | rēgī | iūdicī | virtū´tī | -ī |
| Acc. | rēgem | iūdicem | virtū´tem | -em |
| Abl. | rēge | iūdice | virtū´te | -e |
| Plural | ||||
| Nom. | rēgēs | iūdicēs | virtū´tēs | -ēs |
| Gen. | rēgum | iūdicum | virtū´tum | -um |
| Dat. | rēgibus | iūdicibus | virtū´tibus | -ibus |
| Acc. | rēgēs | iūdicēs | virtū´tēs | -ēs |
| Abl. | rēgibus | iūdicibus | virtū´tibus | -ibus |
1. The base or stem is found by dropping -is in the genitive singular.
2. Most nouns of two syllables, like prīnceps (prīncip-), mīles (mīlit-), iūdex (iūdic-), have i in the base, but e in the nominative.