• المعرفه :

Is called for nouns that are specified and it can includes :

-Names of people , countries and cities like : محمد ، هند ، مكة ، مصر

-Pronouns like :

أنا ، أنت ، هو

-Nouns that are preceded by ( ال ) like :

المدرسه ، المنزل ، المعلم

- Demonstrative pronouns like :

هذا ، هذه ، هؤلاء

- connected words like :

التي ، الذي

Hi Mrs. Pepperpot, It's very simple. الاسم النكرة is the indefinite noun which doesn't refer to a specific thing, a common noun like: a pen (we didn't specify which pen). الاسم المعرّف is the definite noun. Example1: فتاةٌ، رجلٌ، سيارةٌ they have tanwin at the end (double vowl) and don't have (ال) at the beginning. Example2: الفتاةُ، الرجلُ، السّيّارةُ they have (ال) in the beginning, and don't have double vowl.