MASCULINE NOUN

Masculine: Male persons, animals days of the week, months and seasons, alcoholic beverage (but: das Bier!), geographical directions and most phenomena connected to the weather.

Nouns ending in -ig -ing -ast -ling -ich -or -us -m (usually), -er when derived from a verb, nouns derived from the stem of a strong (irregular) verb and not end in -t or -e.

Examples in German:

the man	der Mann
the father	der Vater
the American	der Amerikaner
the teacher	der Lehrer
the boss	der Chef
the psychologist	der Psychologe
Monday	der Montag
April	der April
the winter	der Winter
the north	der Norden
the butterfly	der Schmetterling
the carpet	der Teppich
the Tutor	der Tutor
communism	der Kommunismus
brother	der Bruder
uncle	der Onkel
son	der Sohn
teacher(male)	der Lehrer
salesclerk(male)	der Verkäufer

Read More:
Femenine Nouns
Neuters Nouns
Number Nouns
Compound Nouns