The research aims to uncover Al-Baghdadi's critical and rhetorical double terminology, which he mentioned in his book (The Law of Rhetoric in Criticism of Prose and Poetry).Accordingly, the study was divided into three sections. The first one shed light on the dual poetic terms: (reconsideration, return, metaphor and exposure), and the second study dealt with the double prose terms: (assonance, duplication, chatter and exclusion), and the double and common terms between poetic and prose, namely: (reverse and switching), and the search for its multi-linguistic and idiomatic connotations. Al-Baghdadi considered the terms of awareness, return, metaphor, and exposure among the terms related to poetry rhetoric and criticism without prose, and he singled out the terms rhetoric and duality in prose eloquence and criticism without poetry, and he made the term opposite and switch from the terms that come out to the section of common terms between poetry and prose.