The Fifth Declension.

Genitive singular -ē̆ī, genitive plural -ē-rum.

[596]. Stems in -ē- are substantive only, and feminine.

[597]. diēs, day, is always masculine in the plural, and commonly in the singular; but the feminine is common when diēs denotes length of time or a set day. merīdiēs, midday, is masculine and singular only.

[598]. The nominative of stems in -ē- ends, including the stem vowel, in -ē-s.

[599]. Stems in -ē- are of two classes:

[600]. (1.) Stems of the first class have one or two syllables; there are four of them: rēs, thing, spēs, hope, diēs, day, and fidēs, faith.

Of this class, rēs and diēs have a plural throughout; spēs has only the nominative and accusative plural, and fidēs has no plural.

[601]. Stems in -ē- of the first class are declined as follows:

Examples
Stems
rēs, thing,
rē-, F.
diēs, day,
diē-, M.
Stem and
case endings
Singular
Nom.rēs, a (or the) thingdiēs-es
Gen.rĕ̄i, re͡i, a thing’s, of a thingdiēī, die͡i-ē̆ī, -ēī, -e͡i
Dat.rĕ̄i, re͡i, to or for a thingdiēī, die͡i-ē̆ī, -ēī, -e͡i
Acc.rem, a thingdiem-em
Abl., from, with, or by a thingdiē
Plural
Nom.rēs, (the) thingsdiēs-ēs
Gen.rērum, things’, of thingsdiērum-ērum
Dat.rēbus, to or for thingsdiēbus-ēbus
Acc.rēs, thingsdiēs-ēs
Abl.rēbus, from, with, or by thingsdiēbus-ēbus