Understanding the Term 'Sonorous' in Music Context

In the realm of classical music, composers like Bach and Beethoven are often revered not only for their profound influence on the genre but also for their remarkable capacity to evoke a wide range of emotions through their compositions. Scholars often study the intricate techniques these composers employed, such as the use of counterpoint and harmonic progression, which contribute to the compelling quality of their works. In examining the emotional resonance of these pieces, one particular term that arises frequently is 'sonorous'. What does 'sonorous' mean in this context?