Each form has a basic meaning associated with the general meaning of the root being used. (Forms 11 through 15 are very rare, so people usually just focus on forms 1 through 10, although 9 is also pretty rare). And each trilateral Arabic root can theoretically be transformed into one of fifteen possible verb forms ( الأوزان, al-awzaan).
Most Arabic words are derived from a three-letter (trilateral) root.
