The application of standards is effective for ensuring expected performance of a system in specific scenarios. A key step of standard enaction or implementation is to precisely comprehend standard terminologies via literal comparison. Current methods for such comparison usually rely heavily on labor, which is usually time-consuming and error-prone. With the rapid increase of the number of standard documents, it is essential to develop an approach to automatize the comparison process. In this work, we proposed a methodology for computerized comparison of terms and definitions in standards. The methodology is comprised of three steps: extraction of portable document format (PDF) text, extraction of terms and definitions, and comparison of definitions. (1) According to PDF types, either scanned or digitally created, corresponding methods are provided for converting PDF documents. (2) Regarding terms and definitions extraction, we identified content structures and logical elements and extracted definition sections and terms. (3) Concerning the comparison step, we evaluated terminology similarities from semantic and syntactic aspects. Reliability, availability, maintainability, and safety (RAMS) are crucial attributes to evaluate system performance. In experimental studies, we compared several RAMS standards issued by IEC, IEEE, ISO, and the Society for Automotive Engineering (SAE). The results show that the applied methodology is capable of evaluating similarities of terms and definitions in standards.