eclension end in -us Masculine, and -u Neuter.
They are declined as follows:--

Fructus, m., _fruit_. Cornu, n., _horn_.
SINGULAR. PLURAL. SINGULAR. PLURAL.
_Nom._ fructus fructus cornu cornua
_Gen._ fructus fructuum cornus cornuum
_Dat._ fructui fructibus cornu cornibus
_Acc._ fructum fructus cornu cornua
_Voc._ fructus fructus cornu cornua
_Abl._ fructu fructibus cornu cornibus

Peculiarities of Nouns of the Fourth Declension.

49. 1. Nouns in -us, particularly in early Latin, often form the Genitive
Singular in -i, following the analogy of nouns in -us of the Second
Declension; as, senati, ornati. This is usually the case in Plautus and
Terence.

2. Nouns in -us sometimes have -u in the Dative Singular, instead of -ui;
as, fructu (for fructui).

3. The ending -ubus, instead of -ibus, occurs in the Dative and Ablative
Plural of artus (Plural), _limbs_; tribus, _tribe_; and in dis-syllables in
-cus; as, artubus, tribubus, arcubus, lacubus. But with the exception of
tribus, all these words admit the forms in -ibus as well as those in -ubus.

4. Domus, _house_, is declined according to the Fourth Declension, but has
also the following forms of the Second:--

domi (locative), _at home_;
domo, _from home_;
domum, _homewards_, _to one's home_;
domos, _homewards_, _to their_ (etc.) _homes_

5. The only Neuters of this declension in common use are: cornu, _horn_;
genu, _knee_; and veru, _spit_.

Exceptions to Gender in the Fourth Declension.

50. The following nouns in -us are Feminine: acus, _needle_; domus,
_house_; manus, _hand_; porticus, _colonnade_; tribus, _tribe_; Idus
(Plural), _Ides_; also names of trees (Sec. 15, 2).

* * * * *

FIFTH DECLENSION.

e-Stems.

51. Nouns of the Fifth Declension end in -es, and are declined as
follows:--

Dies, m., _day_. Res, f., _thing_.
SINGULAR. PLURAL. SINGULAR. PLURAL.
_Nom._ dies dies res res
_Gen._ diei dierum rei rerum
_Dat._ diei diebus rei rebus
_Acc._ diem dies rem res
_Voc._ dies