All German nouns belong to one of three genders: masculine, feminine or neuter. It is imperative you learn nouns together with the appropriate definite article , as the ramifications of belonging  to one of these three genders pervade German. Without knowing the gender of a noun you will not, for example, be able to correctly say ‘the  table/door/house’, ‘a table/door/house’, ‘a big table/door/house’, ‘this table/ door/house’, ‘which table/door/house’, or ‘his table/door/house’ as ‘the’,  ‘a’, ‘big’, ‘that’, ‘this’, ‘which’ and ‘his’ will most likely vary as ‘table’ is  masculine, ‘door’ is feminine and ‘house’ is neuter, e.g.

der Tisch/die Tür/das Haus
ein Tisch/eine Tür/ein Haus
ein großer Tisch/eine große Tür/ein großes Haus
dieser Tisch/diese Tür/dieses Haus
welcher Tisch/welche Tür/welches Haus
sein Tisch/seine Tür/sein Haus

You will even be faced by nouns not preceded by a determiner like der/die/das, which indicate the gender of the noun, but where you simply need  to know intuitively what gender the noun is, e.g. frische Milch (fresh milk)  and kaltes Bier (cold beer), where the knowledge that Milch is feminine and  Bier is neuter determines the ending on the preceding adjective.

Learning the gender of each noun is one of the most dificult aspects of  learning German but one you will have to master. There are a few rules that  will give you some assistance in learning the gender of a noun but they only  cover a minority of nouns.

A small minority of German nouns are neuter, possibly no more than 10 per  cent, so if you have no idea of the gender of a noun and are forced to guess,  it would not be wise to opt for neuter. Feminine nouns, as the rules given  below will indicate, are often recognizable as feminine due to their ending.  Nouns that end in -e are overwhelmingly feminine. So few neuter nouns  end in -e that they can be rote learnt, e.g. das Auge (eye), das Ende (end),  das Interesse (interest). Masculine nouns that end in -e are weak nouns ) and nearly all of them refer to masculine  beings and thus their masculine gender is obvious, e.g. der Russe (Russian).  Otherwise you can assume that any noun ending in -e is feminine, e.g. die Decke (ceiling), die Katze (cat), die Tapete (wallpaper).

Sometimes the meaning of a noun serves as an aid to gender. The word for  a ‘painter’, der Maler, must be masculine as it refers to a male being. The  word for a ‘bear’, der Bär, is also masculine as it refers to a large, strong  animal, whereas a ‘mouse’ is die Maus; but this does not help much as the  word for a ‘horse’ is das Pferd.

 But there is a sub-rule here that can help:  if there is a separate word for the male and female of a given animal, e.g.  ‘stallion’ and ‘mare’, those words will be masculine and feminine respectively but the generic word, ‘horse’,  will often be neuter, e.g. das Huhn/der  Hahn/die Henne (chicken/rooster/hen), das Schwein/der Eber/die Sau (pig/
boar/sow). But this rule has its limits too as a ‘duck’ is die Ente and a ‘goose’  is die Gans, but that is because, as in English, the name of the female of the  species is the generic term for the species.

Sometimes gender is determined by the form of the word; certain endings  will always be masculine, feminine or neuter, e.g. die Gelegenheit (opportunity) and die Geschwindigkeit (speed) because all nouns that end in -heitor -keit are feminine (see below).

The rules for gender that follow are far from ideal but they are as good as  it gets. When nouns are joined together to form a compound noun the gender of the new word is the same as that of the last element in  the compound, e.g. die Zeit  der Plan  der Zeitplan (schedule), das Haus  die Tür  die Haustür (front door).