§66. Pure i-Stems
Masculine and Feminine parisyllabic nouns in -is form the Nominative singular by adding s to the stem.
Four stems in bri- and tri- do not add s to form the nominative, but drop i and insert e before r. These are imber, linter, ūter, venter.
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.