Literally, ‘tajwid‘ means improvement and perfection. If you do something with tajwid it means you are trying to do it with the utmost quality and in the most perfect way possible. The term Tajwid Rules, refers to the science concerned with correct recitation and pronunciation of the Qur’anic words and verses. The relationship is clear between the literal meaning of the word and its technical usage; the literal meaning revolves around perfecting an action or a performance, which is the recitation of the Qur’an as far as the science of Tajwid is concerned.
After the rapid spread of Islam in its early centuries, especially among non-Arabs, Muslim scholars deemed it necessary to put down a set of rules that serve as a reference for the Qur’an learners. So, Tajwid has been the reference for people who wished to recite the Qur’an in a correct manner. This, however, does not deny the fact that the Qur’an cannot be learned independently, without the assistance of a skilled teacher. The unique isnad-based system of learning Qur’an continued to be the recognized way for teaching students how to recite the Qur’an and for training them on Tajwid. In the isnad-based system, a student recites the whole Qur’an by heart, from the beginning to the end, fulfilling the rules of Tajwid to a certified Qur’an teacher, and then the student is certified by the teacher to be qualified to recite and teach the Qur’an. The certificate is called ijazah (license). A typical ijazah lists the teachers of the granting sheikh (the isnad or sanad , an unbroken chain of teachers that goes back to the Prophet).