61. The following nouns have one meaning in the Singular, and another in
the Plural:--

SINGULAR. PLURAL.
aedēs, _temple_; aedēs, _house_.
auxilium, _help_; auxilia, _auxiliary troops_.
carcer, _prison_; carcerēs, _stalls for racing-chariot_.
castrum, _fort_; castra, _camp_.
cōpia, _abundance_; cōpiae, _troops_, _resources_.
fīnis, _end_; fīnēs, _borders_, _territory_.
fortūna, _fortune_; fortūnae, _possessions_, _wealth_.
grātia, _favor_, grātiae, _thanks_.
_gratitude_;
impedīmentum, impedīmenta, _baggage_.
_hindrance_;
littera, _letter_ (of the litterae, _epistle; literature_.
alphabet);
mōs, _habit_, _custom_; mōrēs, _character_.
opera, _help_, _service_; operae, _laborers_.
(ops) opis, _help_; opēs, _resources_.
pars, _part_; partēs, _party_; _rôle_.
sāl, _salt_; sălēs, _wit_.

* * * * *

B. ADJECTIVES.

62. Adjectives denote _quality_. They are declined like nouns, and fall
into two classes,--