Allen & Greenough · Part First — Words and Forms › THIRD DECLENSION (CONSONANT AND i-STEMS)

§61. Liquid and Nasal Stems (l, n, r)

In Masculine and Feminine nouns with liquid and nasal stems the Nominative is the same as the stem.

Exceptions are the following:—

Stems in ōn- drop n in the nominative: as in legiō, stem legiōn-.
Stems in din- and gin- drop n and keep an original ō in the nominative: as in virgō, stem virgin-.¹
¹ These differences depend in part upon special phonetic laws, in accordance with which vowels in weakly accented or unaccented syllables are variously modified, and in part upon the influence of analogy.
Stems in in- (not din- or gin-) retain n and have e instead ofi in the nominative: as in cornicen, stem cornicin-.²
² These differences depend in part upon special phonetic laws, in accordance with which vowels in weakly accented or unaccented syllables are variously modified, and in part upon the influence of analogy.
Stems in tr- have -ter in the nominative: as, pater, stem patr-.³
³ These, no doubt, had originally ter- in the stem, but this had become weakened to tr- in some of the cases even in the parent speech. In Latin only the nominative and vocative singular show the e. But cf.Māspitris andMāspiteris (Mā[r]s-piter), quoted by Priscian as old forms.

J. H. Allen and J. B. Greenough, New Latin Grammar (Boston: Ginn, 1903). Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities.