المعنى الاصطلاحي :

Changing the pronunciation of a word, regardless of whether this changes the meaning.

الشرح المختصر :

"Lahn" (solecism/mispronunciation) is to wrongly recite the Holy Qur’an, whether this happens due to a person's ignorance of proper recitation rules or as a deliberate attempt to refine the performance of recitation to conform to a certain melody. It is of two types: 1. Hidden "lahn": when rules of correct recitation are not observed but without impacting the meaning. This type of solecism can be recognized only by specialists. 2. Apparent "lahn": when a word is mistakenly read by violating both the rules of "tajweed" (recitation) and the structure of the word, regardless of whether this results in a change of meaning. It can influence words, letters, or even diacritical marks. It usually happens by adding or omitting a letter or a word or by replacing a diacritical mark by another.

التعريف اللغوي المختصر :

"Lahn": mistake, deviation from the right. Original meaning: changing the course of something. Other meanings: sound, refining speech, intonation.