Single-Termination Third Declension Adjectives

Here’s a review of triple- and twin-termination adjectives, covered in earlier posts:

  • Triple-termination: ācer, ācris, ācre (sharp)
  • Twin-termination: levis (m/f), leve (light)

Formation of Single-Termination Third Declension Adjectives

These are complicated because they take several possible consonant stems. That said, their declension is more-or-less equivalent to third declension i-stem nouns (nūbes, nūbis or maremaris)

atrōx, actrōcis, fierce

A few things to note:

  • The ablative singular may be either atrōcī or (less often) atrōce
  • The neuter plurals all feature the istem (-ia, -ium, -ibus, etc.)
  • The masculine and feminine plural accusative may (rarely) be atrocīs

Here are a few more nouns to consider:

egēns, egentis: needy

praeceps, praecipitis: headlong

pārparis: equal, alike

ūber, ūberis: fruitful, copious

The Essential AG: 118

Famous Phrase: cēterīs pāribus [all other things being equal]

(an ablative absolute, denoting non-variable components of scientific experiments or other forms of structural reasoning)


Third Declension Twin-Termination Adjectives

Adjectives of the third declension have either one, two or three gendered endings.

  • Triple-termination: ācer, ācris, ācre (sharp) [see here]
  • Twin-termination: levis (m/f), leve (light)
  • Single-termination: …these are complicated. I’ll address them in a coming post

Twin-Termination Formation

Adjectives of the third declension with two terminations are declined as follows:

Here are some additional twin-termination thirds to practice declining:

  • faenebris, faenebre: lent at interest
  • fūnebris, fūnebre: funereal
  • illūstris, illūstre: shining, famous
  • lūgubris, lūgubre: mournful
  • mediocris, mediocre: (usually) moderate; (rarely) ordinary
  • muliebris, muliebre: effeminate

The Essential AG: 116

Third Declension Triple-Termination Adjectives

Adjectives of the third declension have either one, two or three gendered endings.

  • Triple-termination: ācer, ācris, ācre (sharp)
  • Twin-termination: levis (m/f), leve (light)
  • Single-termination: …these are complicated. I’ll address them in a coming post

Triple-Termination Formation

Triple-Termination Third Declension Adjectives are declined as follows:

Here are additional triple-declensions thirds to practice declining:

  • alacer, alacris, alacre: lively, cheerful
  • campester, campestris, campestre: flat
  • celeber, celebris, celebre: famed, crowded
  • equester, equestris, equestre: equestrian
  • palūster, palūstris, palūstre: boggy
  • pedester, pedestris, pedestre: pedestrian, ordinary
  • puter, putris, putre: rotting
  • salūber, salūbris, salūbre: healthy
  • silvester, silvestris, silvestre: woodland
  • terrester, terrestris, terrestre: terrestrial
  • volucer, volucris, volucre: aerial
  • octōber, octōbris, ocrōbre: of October
  • (likewise with all menstrual [monthly] adjectives)

Do note: the triple-termination design was developed relatively late, so you may encounter some or all of these adjectives as twin-termination adjectives, with either the masculine or the feminine representing either the masculine or the feminine in early Latin prose and poetry [e.g. homō alacris or fēmina alacer would be acceptable] (AG, 115 n1)

Also, celer, celeris, celere (swift) is an odd bird.

The Essential AG: 115-115a

Gender of Latin Plant Nouns

Feminine. As a rule, they are feminine.

Here are some examples, with corresponding photographs:

rosa, -ae : rose

caltha, -ae : marigold

īlex, īlicis : Holm Oak

hedera, -ae : ivy
















pīnus, pīnī : (Italic) pine [yes, still feminine]

There are exceptions to this rule, as one may expect.

  • robur, -ōris : oak (n)
  • acer, acēris : maple  (n)

For a better sense of the gender distribution (largely feminine with some neuters), here’s a list of all the Latin names of ‘British’ foliage. Pay attention to the species name (and adjective) to clarify the gender of third declension nouns.

According to A&G, “many names of plants in -us vary between the second and fourth declensions.” They then give no examples. Can you think of any?

The Essential AG: 32, 32b

Famous Phrase: sub rosā [beneath the rose]

A phrase denoting secrecy. The rose was associated with silence, as was given as the symbol of Harpocrates, the god of silence at Rome. In the Middle Ages, a rose hanging over the entrance chamber of a given committee room represented a call for silence about the content of the committee’s discourse.