«Asas al-Balaghah» (The Foundation of Eloquence) is a thesaurus and dictionary of figurative speech by al-Zamakhshari.

Zamakhshari authored the work in part, to reconcile what he viewed as the miraculous nature of the Qur'an with his theological views.

It was the earliest Arabic lexicography to be organized in a completely alphabetical form, and was noteworthy for its attention to metaphorical meanings.

Words therein are listed in order from the first of their three component letters to the last, excluding complicated forms derived from roots as well as rare roots such quadrilaterals and quintilaterals.

Zamakhshari's goal was to catalogue both the literal and figurative meanings of Arabic words, and he used examples from the Qur'an and hadith for both.

He viewed words almost as living organisms that were given life by the way they were used in rhetoric.