The third pattern, مِفْعَالٌ, has:
Word / formMeaning / explanation
مِفْعَالٌsingular.
مِفْعَالَانِdual.
مَفَاعِيلُbroken plural.
For example, مِفْتَاحٌ is one key, مِفْتَاحَانِ two keys and مَفَاتِيحُ several keys.
The plural مَفَاعِيلُ must not be confused with مَفَاعِلُ, the plural template used for the first two source patterns.
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Ism al-Ālah: Definition, Three Patterns, Paradigms and Formation
The third pattern, مِفْعَالٌ, has:
Word / formMeaning / explanation
مِفْعَالٌsingular.
مِفْعَالَانِdual.
مَفَاعِيلُbroken plural.
For example, مِفْتَاحٌ is one key, مِفْتَاحَانِ two keys and مَفَاتِيحُ several keys.
The plural مَفَاعِيلُ must not be confused with مَفَاعِلُ, the plural template used for the first two source patterns.