Idaafa

Idaafa  الاضافة. The Idaafa structure is usually made of two or more nouns that are semantically related and in a sequence. Sometimes it sounds like a sort of "possessive" relationship, where English could use "of" or "'s" .The first term of the Idaafa might be in any case and should not take Nunation or a definite article. The Second term of the Idaafa, on the other hand, is always in the genitive case and may take Nunation or a definite article.

the language professor:

استاذ ُ اللغةِ    ،    استاذ َ اللغةِ   ،   استاذِ اللغةِ

    a language professor:  

استاذ ُ لغةٍ      ،    استاذ َ لغةٍ     ،   استاذ ِ لغةٍ

      If you encounter a cluster of nouns, then you should try to find out if it is an Idaafa structure.