ما مثنى وجمع كلمة وعاء و فناء؟

The dual form of the word “container” is “two containers” in the nominative case and “two containers” in the accusative and genitive cases. Its plural is “containers.”
The dual form of the word “courtyard” is “two courtyards” in the nominative case and “two courtyards” in the accusative and genitive cases. Its plural is “courtyards.”