[252.] Adjectives learned thus far have had a different form in the nominative for each gender, as, bonus, m.; bona, f.; bonum, n. Such an adjective is called an adjective of three endings. Adjectives of the third declension are of the following classes:

I. Adjectives of three endings—
a different form in the nominative for each gender.
II. Adjectives of two endings—
masculine and feminine nominative alike, the neuter different.
III. Adjectives of one ending—
masculine, feminine, and neuter nominative all alike.

[253.] Adjectives of the third declension in -er have three endings; those in -is have two endings; the others have one ending.

CLASS I

[254.] Adjectives of Three Endings are declined as follows:

ācer, ācris, ācre, keen, eager
Stem ācri-Base ācr-
SingularPlural
MASC.FEM.NEUT.MASC.FEM.NEUT.
Nom.ācerācrisācreācrēsācrēsācria
Gen.ācrisācrisācrisācriumācriumācrium
Dat.ācrīācrīācrīācribusācribusācribus
Acc.ācremācremācreācrīs, -ēsācrīs, -ēsācria
Abl.ācrīācrīācrīācribusācribusācribus
CLASS II

[255.] Adjectives of Two Endings are declined as follows:

omnis, omne, every, all1
Stem omni-Base omn-
SingularPlural
MASC. AND FEM.NEUT.MASC. AND FEM.NEUT.
Nom.omnisomneomnēsomnia
Gen.omnisomnisomniumomnium
Dat.omnīomnīomnibusomnibus
Acc.omnemomneomnīs, ēsomnia
Abl.omnīomnīomnibusomnibus

1. omnis is usually translated every in the singular and all in the plural.