5. Nouns in -s preceded by a consonant.
a. Masculine: dēns, tooth; fōns, fountain; mōns, mountain; pōns, bridge.
6. Nouns in -dō.
a. Masculine: cardō, hinge; ōrdō, order.
[46]. Exceptions to the Rule for Neuters.
1. Nouns in -l.
a. Masculine: sōl, sun; sāl, salt.
2. Nouns in -n.
a. Masculine: pecten, comb.
3. Nouns in -ur.