2. Names of _Trees_, and such names of _Towns_ and _Islands_ as end in -us,
are Feminine; as,--

quercus, _oak_; Corinthus, _Corinth_; Rhodus, _Rhodes_.

Other names of towns and islands follow the gender of their endings (see
_B_, below); as,--

Delphī, n.; Leuctra, n.; Tībur, n.; Carthāgō, f.

3. Indeclinable nouns, also infinitives and phrases, are Neuter; as,--

nihil, _nothing_; nefās, _wrong_; amāre, _to love_.

NOTE.--Exceptions to the above principles sometimes occur; as, Allia (the
river), f.

_B. Gender determined by Ending of Nominative Singular._

The gender of other nouns is determined by the ending of the Nominative
Singular.[11]

NOTE 1.--_Common Gender._ Certain nouns are sometimes Masculine, sometimes
Feminine. Thus, sacerdōs may mean either _priest_ or _priestess_, and is
Masculine or Feminine accordingly. So also cīvis, _citizen_; parēns,
_parent_; etc. The gender of such nouns is said to be _common_.

NOTE 2.--Names of animals usually have grammatical gender, according to the
ending of the Nominative Singular, but the one form may designate either