3. A Genitive and Dative form in -ē sometimes occurs; as, aciē.
4. With the exception of diēs and rēs, most nouns of the Fifth Declension are not declined in the Plural. But aciēs, seriēs, speciēs, spēs, and a few others are used in the Nominative and Accusative Plural.
Gender in the Fifth Declension.
[53]. Nouns of the Fifth Declension are regularly Feminine, except diēs, day, and merīdiēs, mid-day. But diēs is sometimes Feminine in the Singular, particularly when it means an appointed day.
DEFECTIVE NOUNS.
[54]. Here belong—
1. Nouns used in the Singular only.
2. Nouns used in the Plural only.
3. Nouns used only in certain cases.
4. Indeclinable Nouns.
Nouns used in the Singular only.
[55]. Many nouns, from the nature of their signification, are regularly used in the Singular only. Thus:—