With the increased penetration of screen reading software, effective audio rendering of equations can significantly assist in making many electronic mathematics documents accessible. However, linear syntactic rendering of equations not only creates a considerable cognitive load, even for relatively simple equations, but also becomes crucial in more advanced mathematical subjects where the precise and correct interpretation of symbols is essential. To overcome this challenge, we are working on a procedure to extract contextual semantics for mathematical expressions from the surrounding text. In this paper, we will present one of its modules: the Semantic Extractor. This module aids in extracting semantics from the concordance that contains valid mathematical definitions. This approach enables contextually aware audio rendering of complex mathematical expressions, rather than relying solely on syntactic rendering.