The possessive article
Possessive articles indicate to whom or what something belongs. For example: Is this your pen? No, this is my pen.
A conjunction joins words or groups of words. Some conjunctions in German are und (and), oder (or), aber (but), weil (because), and dass (that).
An infinitive is the base form of a verb, which has not been changed to show tense or given any endings. In German, an infinitive always ends in -en or -n and is the form of the verb found in the dictionary (e.g. machen, gehen).
Conjugation refers to a set of endings (and sometimes vowel changes) for verbs that help to mark person and tense. For example, “to be” = I am, you are; sein = ich bin, du bist, etc.
Declension refers to the change of article, adjective or noun depending on case. For example: Der nette Mann kauft der jungen Frau einen schönen Blumenstrauß.
Cases indicate the function of a noun in a sentence. In German, the subject of a sentence is in the Nominative case, the direct object in the accusative case and the indirect object in the Dative case. For example: Der nette Mann kauft der jungen Frau einen schönen Blumenstrauß.