Appendix:Latin first declension

Description
Latin words of the first declension have an invariable stem. The nominative singular form consists of the stem and the ending -a, and the genitive singular form is the stem plus -ae. The predominant letter in the endings of this declension is a. From the perspective of historical linguistics, they can alternatively be analyzed as having a vowel-final stem ending in ā (corresponding to Greek stems ending in η, ᾱ, and ᾰ), and so can be called ā-stem nouns.

First-declension nouns typically have feminine grammatical gender. This includes not only many nouns referring to female living beings (human or animal), such as and, but also many nouns referring to inanimate objects or abstractions, such as  and. However, a minority of first-declension nouns are masculine, in exception to the usual rule. Most masculine first-declension nouns are animate nouns that refer to males or to persons of unspecified sex. They include:
 * a few common nouns referring to occupations held predominantly by men, such as, , , ,.
 * Deverbal compounds referring to people, such as, derived by adding the suffix to the compound verb . The endings , ,  in particular show some productivity in forming new compounds.
 * Proper names of male persons (since these are always grammatically masculine in Latin, regardless of their form), e.g., ,.

Inanimate first-declension nouns are rarely masculine, but examples can be found in the following categories:
 * Sometimes river names, which were often (but not always) masculine in Latin.
 * Nouns of foreign origin, including various nouns taken from Greek (see below).

Compounds of the type are usually grammatically masculine (like other masculine nouns, they can have generic signification when used indefinitely), but there are examples of some of them being treated as grammatically feminine when used with specific reference to a female person. Thus, dictionaries often categorize words like as 'common gender' nouns. They are often used attributively with other nouns. Examples of this in Classical Latin can often be interpreted as showing apposition of two nouns (a common construction in Latin). However, the distinction between nouns and adjectives in Latin was somewhat permeable, and some words of this type eventually came to show increasingly similar behavior to adjectives (for example, by being used to modify neuter nouns). As a result, some (such as ) may be described as adjectives of common gender.

The first declension also holds three types of Greek nouns, derived from Ancient Greek's first (alpha) declension. They are declined irregularly in the singular. Occasionally, these Greek nouns may be declined as if they were native Latin nouns, e.g. nominative athlēta may be used instead of the original athlētēs.

Peculiarities

 * The older genitive singular termination is -ās. This is often used with familia as in pater familiās and māter familiās.
 * In poetry, the genitive singular -āī occurs. Aquāī for aquae.
 * The genitive plural ending can appear as instead of -ārum in certain circumstances. Caelicolum for caelicolārum.
 * Because first declension nouns and second declension nouns display an –īs in the dative and ablative plural, words like equus (horse) and equa (mare) will end up looking alike in these cases. However, if a distinction must be made, equīs for 'mares' would become equābus in the dative and ablative plural. For this reason, the ending -ābus was regularly used in the dative and ablative plurals of the nouns dea (goddess) and filia (daughter).

Declension paradigms
Examples:
 * stēlla, -ae
 * rosa, -ae
 * nauta, -ae
 * Rōma, -ae (with locative, without plural)

Adjectives

 * Adjectives of the first declension are of "common" gender, meaning the same forms are used for masculine and feminine. The use of these adjectives with neuter nouns is very rare and poorly attested in Classical Latin, but there are a handful of examples showing neuter genitive singular ("Tempore rūricolae patiēns fit taurus arātrī", Ovid Tristia 4.6.1) or neuter ablative singular forms ("vīnō aliēnigenā", Aulus Gellius, Noctes Atticae 2.24.2.8 and "dē indigenā vīnō", Pliny, Naturalis Historia 14.72.3). Nevertheless, the form or even existence of the neuter is questionable in some cases.
 * Neuter forms presumably would match the masculine/feminine forms in cases other than the nominative/accusative/vocative. Latin neuter nouns and adjectives always share the same form among those three cases, and almost always end in -a in the plural. Based on these rules, we might infer the ending -a for the neuter nominative/accusative/vocative in both singular and plural, and some such neuter forms ending in -a are in fact attested in later authors. The grammarian Pompeius, who likely lived in the fifth century, considers the word advena to be common to all three genders, saying that it is possible to find the phrase "mancipium advena". Tertullian used terrigena as a neuter plural in animālia terrigena (but this may be regarded as a nonclassical feature).
 * However, a complicating factor is that many adjectives of this type eventually developed alternative forms declined as first/second declension adjectives in -us, -a, -um. This makes it ambiguous whether attested neuter plural forms ending in -a (nom/acc/voc) or -īs (dat/abl) are first-declension or second-declension forms. For example, Priscian cites "alienigena studia" from Valerius Maximus, but interprets alienigena as a second-declension plural form (corresponding to a singular alienigenum), arguing that there are no neuters in the first or fifth declension. Gaffiot cites Seneca's "alienigena [...] sacra" (Ep. 108.22) and Lucretius's "ex alienigenis rebus" (DRN 1.865) as examples of, even though unambiguously second-declension forms of this word do not appear in the works of Seneca or Lucretius.
 * The same ambiguity does not apply to genitive plural forms ending in -ārum, and there are some examples of these forms modifying neuter nouns in New Latin authors, such as animalium indigenarum/cornupetarum.

Examples:

Greek nouns
Notes:
 * The plural and dative singular forms equal the forms of pure Latin words.

Examples:
 * nymphē, -ēs
 * comētēs, -ae (also: comēta, -ae );  dynastēs, -ae
 * xiphiās, -ae