(1) a:-stems, traditionally called first declension nouns;
    these are mostly feminine, with a few masculine
    exceptions (e.g., <agricola> 'a farmer, a peasant').
    Note that in medieval Latin the <-ae> endings usually
    appear as <-e>.

          Sing.  Plur.
         --------------
    Nom   -a     -ae
    Gen   -ae    -arum
    Dat   -ae    -is
    Acc   -am    -as
    Abl   -a     -is

    Feminine names were often Latinized as a:-stems, e.g.,
    <Adalgisa>, gen. <Adalgis(a)e>.

(2) o-stems, traditionally called second declension nouns;
    these are masculine and neuter.  The main masculine
    subtype:

          Sing.  Plur.
         --------------
    Nom   -us    -i
    Gen   -i     -orum
    Dat   -o     -is
    Acc   -um    -os
    Abl   -o     -is

    The main neuter subtype differs only in having <-um> in
    the nom. sing. and <-a> in the nom. and acc. plur.  Some
    masc. o-stems (e.g., <servos> 'a servant') have <-os> in
    the nom. sing. and <-om> in the acc. sing., and some
    others (e.g., <vir> 'a male person') have no ending in
    the nom. sing. but are otherwise normal.

    Masculine names were often Latinized as o-stems, e.g.,
    <Hubertus>, gen. <Huberti>.

(3) What is traditionally called the third declension
    comprises old i-stems and consonant stems and includes
    nouns of all three genders.  In these nouns the stem of
    the nom. sing. is often a bit different from the stem of
    all of the other forms and can show other complications;
    I'll give a few examples after presenting the basic sets
    of endings.  For masc. and fem. nouns of this declension
    we have the following endings, where the asterisk is a
    reminder to watch out for exceptions:

          Sing.  Plur.
         --------------
    Nom   -s*    -es
    Gen   -is    -(i)um
    Dat   -i     -ibus
    Acc   -em    -es
    Abl   -e     -ibus

    The neuters are similar, but they have no ending in the
    nom. and acc. sing., and they have <-a> in the nom. and
    acc. plur.

    A typical masc. consonant stem is <rex> 'a king'.  The
    stem is actually <reg-> (e.g., nom. sing. <regis>, abl.
    plur. <regibus>, etc.), but in the nom. sing. an
    original *<regs> was simplified to <rex>.  The same sort
    of thing happened to the fem. <nox> 'a night', whose
    stem is actually <noct-> (gen. sing. <noctis>, gen.
    plur. <noctium>, etc.).  Another masc. consonant stem,
    one in which the nom. sing. is harder to explain, is
    <miles> 'a soldier': the stem is actually <milit-> (nom.
    sing. <militis>, nom. plur. <milites>, etc.).  There are
    even some masc. and fem. nouns of this general type that
    lack any sign of <-s> in the nom. sing.: masc. <vigil>
    'a fireman', whose other cases are built normally on the
    stem <vigil->, and fem. <mater> 'a mother', whose other
    cases are built normally on the stem <matr->, are
    examples.

    Some of the neuters are exceptions to the rule that all
    of the forms except the nom. sing. use the same stem: in
    third declension neuters the acc. sing. is always
    identical to the nom. sing.  Thus we have for instance
    neuter <nomen> 'a name', with acc. sing. also <nomen>
    but whose other forms are all built on the stem
    <nomin->.

    In the Middle Ages quite a few names were Latinized as
    third declension nouns.  The most common masc. type is
    represented by <Wido> 'Guy':

    Nom: Wido
    Gen: Widonis
    Dat: Widoni
    Acc: Widonem
    Abl: Widone

    The most common feminine type is represented by
    <Adalgardis>:

    Nom: Adalgardis
    Gen: Adalgardis
    Dat: Adalgardi
    Acc: Adalgardem
    Abl: Adalgarde

(4) u-stems, traditionally called fourth declension nouns;
    they can be of any gender, but most of them are masc.
    The masc. and fem. nouns have the following endings:

          Sing.  Plur.
         --------------
    Nom   -us    -us
    Gen   -us    -uum
    Dat   -ui    -ibus
    Acc   -um    -us
    Abl   -u     -ibus

    The neuters are very simple: in the sing. they have <-u>
    in every case except the gen., which has <-us>, and in
    the plural they're like the masc. and fem. nouns except
    that they have <-ua> in the nom. and acc.

(5) The traditional fifth declension is a mixed bag, more or
    less a catch-all category for everything else.  All
    fifth declension nouns are fem. except <dies> 'a day'
    and <meridies> 'midday, noon', which are masc. (except
    that <dies> is sometimes fem. in the sing.), and most
    show some irregularities.  The only two that I know are
    completely regular are <dies> and <res> 'a thing', so
    I'll simply give their declensions:

          Sing.        Plur.
         -----------------------
    Nom:  dies, res    dies, res
    Gen:  diei, rei    dierum, rerum
    Dat:  diei, rei    diebus, rebus
    Acc:  diem, rem    dies, res
    Abl:  die, re      diebus, rebus