edited by Meagan Ayer et al.

Variable Nouns

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104. Many nouns vary either in Declension or in Gender.

105. Nouns that vary in Declension are called heteroclites.1

a. Colus (f.), distaff; domus (f.), house (see § 93), and many names of plants in -u, vary between the 2nd and 4th Declensions.

b. Some nouns vary between the 2nd and 3rd:

iūgerum, , , abl. or -e, plural -a, -um, -ibus
Mulciber, gen. -berī and -beris
sequester, gen. -trī and -tris
vās, vāsis, and (old) vāsum, (§ 79.e).

c. Some vary between the 2nd, 3rd, and 4th.

penus, penum, gen. penī and penoris, abl. penū.

d. Many nouns vary between the 1st and 5th (see § 98.c).

e. Some vary between the 3rd and 5th.

requiēs, gen. -ētis, dat. — , acc. -ētem or -em, abl.  (once
famēs, regularly of the 3rd declension, abl. famē (§ 76, Note 1)
pūbēs (m.) has once dat. pūbē (in Plautus).

f. Pecus varies between the 3rd and 4th, having pecoris, etc., but also nom. pecū, abl. pecū; plural pecua, gen. pecuum.

g. Many vary between different stems of the same declension:

femur (n.), gen. -oris, also -inis (as from † femen)
incur (n.), gen. iecinoris, iocinoris, iecoris
mūnus (n.), plural mūnera and mūnia.

106. Nouns that vary in Gender are said to be heterogeneous.2

a. The following have a masculine form in -us and a neuter in -um:

balteus, cāseus, clipeus, collum, cingulum, pīleus, tergum, vāllum

with many others of rare occurrence.

b. The following have in the plural a different gender from that of the singular:

balneum (n.) bathbalneae (f.) baths (an establishment)
caelum (n.) heavencaelōs [(m.) acc., Lucretius]
carbasus (f.) a sailcarbasa, -ōrum (n.) sails
dēlicium (n.) pleasuredēliciae (f.) pet
epulum (n.) feastepulae (f.) feast
frēnum (n.) a bitfrēnī (m.) or frēna (n.) a bridle
iocus (m.) a jestioca (n.), iocī (m.) jests
locus (m.) place

loca (n.), locī (m.) usually topics,
passages (in books)

rāstrum (n.) a rakerāstrī (m.), rāstra (n.) rakes

Note— Some of these nouns are heteroclites as well as heterogeneous.

107. Many nouns are found in the Plural in a peculiar sense:

aedēs, -is (f.) templeaedēs, -ium house
aqua (f.) water

aquae mineral springs,
a watering-place

auxilium (n.) helpauxilia auxiliaries
bonum (n.) a goodbona goods, property
carcer (m.) dungeoncarcerēs barriers (of race-course)
castrum (n.) fortcastra camp
comitium (n.) place of assembly

comitia an election,

cōpia (f.) plentycōpiae stores, troops
fidēs (f.) harp-stringfidēs lyre
fīnis (m.) endfīnēs bounds, territories
fortūna (f.) fortunefortūnae possessions

grātia (f.) favor
(rarely, thanks)

grātiae thanks
(also, the Graces)

hortus (m.) a gardenhortī pleasure-grounds
impedīmentum (n.) hindranceimpedīmenta baggage
littera (f.) letter (of alphabet)litterae epistle, literature
locus (m.) place [pl. loca (n.)]locī3 topics, places in books
lūdus sportlūdī public games
mōs (m.) habit, custommōrēs character
nātālis (m.) birthdaynātālēs descent, origin
opera (f.) workoperae day-laborers (“hands”)
[ops] opis (f.) help (§ 103.f.1)opēs resources, wealth
pars (f.) partpartēs part (on the stage), party
rōstrum (n.) beak of a shiprōstra speaker's platform
sāl (m. / n.) saltsalēs witticisms
tabella (f.) tablettabellae documents, records



1. That is, “nouns of different inflections” (ἔτερος another, and κλινω to inflect).
2. That is, “of different genders” (ἕτερος  another, and γένος  gender).
3. In early writers the regular plural.

Suggested Citation

Meagan Ayer, Allen and Greenough’s New Latin Grammar for Schools and Colleges. Carlisle, Pennsylvania: Dickinson College Commentaries, 2014. ISBN: 978-1-947822-04-7. http://dcc.dickinson.edu/grammar/latin/variable-nouns