Heavy Construction
The Allen and Greenough is still under construction;
so some links may not work quite the way you would expect.
FOURTH DECLENSION.
88.
The Stem of nouns of the Fourth Declension ends
in u-. This is usually weakened to
i before -bus. Masculine and Feminine nouns form the
nominative by adding s; Neuters have
for nominative the simple stem, but with ú (long).