Word: Wahī

Meaning: direct revelation by God through the medium of the Archangel Gabriel 

Word: Ilhām

Meaning: divine inspiration 

Word: Nabī

Meaning: Prophet 

Word: Sunnah

Meaning: Sunnah is the tradition, practice or culture of the Prophet. 

Word: Hadīth

Meaning: The oral tradition where the Sunnah is preserved.

Word: Rasūl

Meaning: Messenger who brings a whole system of laws. All rasūls are nabīs.