Mutter, Haifisch, Messer = mother, shark, knife, are nouns, which are words you can put 'the' or 'a' in front of, and describe a person, place, thing, animal or idea.  In English nouns, place names and people's names start with a capital letter - in German, ALL nouns start with a capital letter, no exception.  So words like Dog, Thought, Paris, Man, Woman, & Child would all have initial capitals.  Or in Rammspeak song titles, so would Shark, Mother, Longing, Angel, my Heart burns.

Another difference with German nouns is that they all have a gender, and unfortunately there are three of them!  French has two, - masculine & feminine (think le and la), but German goes one better and uses three:  masculine, feminine and neuter.  This doesn't make sense to us in English, as we end up with masculine spoons, feminine forks and neutral knives.  We easily say 'the knife, the fork the spoon', but in German, you cannot know how to say 'the' until you know the gender of the noun you are using.

If I tell you that der [dare] masculine, die [dee] feminine and das [dass-uh] neuter are all words for 'the', you can correctly place them with the right noun.  So der Loeffel (spoon), die Gabel (fork), das Messer (knife.)  Sometimes words are logical and follow English examples - to make a prince feminine in English, we add 'ess' or 'ss' = princess (like priest, priestess, host and hostess.) In German, it's the same, Prinz, Prinzessin, so when you see -in at the end of a noun that describes a person, she's more often than not female.

The word 'the' will also give away the noun's gender - der Prinz, die Prinzessin. German nouns that end in -er are usually masculine, and relate to a person's trade (as in English baker,sailor, solider, doctor.)  Der Vater (father), der Baecker (baker), der Schau/spiel/er (actor), but die Schau/spiel/er/in (actress.) Der Arzt (doctor), but die Aerztin (lady doctor.)

The only way to stay sane is to firstly, learn your grammar terms so we have a common reference language:  you now know what a noun is, and I will also let you know that the word 'the' is referred to grammatically speaking as 'the definite article.' Secondly, learn the gender and definite article of each noun off by heart, and do this without questioning why a knife is neuter and a fork is feminine - always learn 'the fork = die Gabel, the knife = das Messer', not just Gabel, Messer.

I'll finish by asking you the following questions (all answers in the blog):  what do these words mean, what are the genders and definite articles of the following German nouns, and should they each start with a capital letter?

Baecker, Schauspielerin, Vater, Messer, Loeffel, Gabel, Prinzessin, Arzt, Prinz, Aerztin, Schauspieler

Good luck!