Masculine are leō , leōnis ; ligō , -ōnis ; sermō , -ōnis ; also cardō , harpagō margō , ōrdō , turbō ; and concrete nouns in -iō : as, pugiō , ūniō , papiliō ; Many nouns in -ō (gen. -ōnis ) are masculinby signification: as, gerō , carrier restiō , ropemaker : and family names (originally nicknames): as, Cicerō , Nāsō . See §§ 236 . c , 255.

acīnacēs , ariēs , celēs , lebēs , pariēs , pēs ;

Nouns in -nis and -guis : as, īgnis , sanguis ; also axis , caulis , collis , cucumis , ēnsis , fascis , follis , fūstis , lapis , mēnsis , orbis , piscis , postis , pulvis , vōmis ;

mūs ;

calix , fornix , grex , phoenīx , and nouns in -ex (gen. -icis ） (§ 85 );

dēns , fōns , mōns , pōns . Some nouns in -is and -ns which are masculine were originally adjectives or participles agreeing with a masculine noun: as, Aprīlis (sc. mēnsis ), M., April; oriēns (sc. sōl ), M., the east; annālis (sc. liber ), M., the year-book.