"(1) A qualitative assessment of correctness, or freedom from error. (2) A quantitative measure of the magnitude of error." (IEEE, "IEEE Standard Glossary of Software Engineering Terminology", 1990)
[accuracy (of measurement):] "Closeness of the agreement between the result of a measurement and a true value of the measurand." International Vocabulary of Basic and General Terms in Metrology, 1993)
"A qualitative assessment of freedom from error or a quantitative measure of the magnitude of error, expressed as a function of relative error." (William H Inmon, "Building the Data Warehouse", 2005)
"Accuracy is the closeness of a measured value to the true value." (Steve McKillup, "Statistics Explained: An Introductory Guide for Life Scientists", 2005)
"A data element’s degree of conformity to an established business measurement or definition. Data precision is the degree to which further measurements or definitions will show the same results." (Jill Dyché & Evan Levy, "Customer Data Integration: Reaching a Single Version of the Truth", 2006)
"Degree of conformity of a measure to a standard or a true value. Level of precision or detail." (Martin J Eppler, "Managing Information Quality" 2nd Ed., 2006)
"The accuracy reflects the number of times the model is correct." (Glenn J Myatt, "Making Sense of Data: A Practical Guide to Exploratory Data Analysis and Data Mining", 2006)
"An aspect of numerical data quality connected with a standard statistical error between a real parameter value and the corresponding value given by the data. Data accuracy is inversely proportional to this error." (Juliusz L Kulikowski, "Data Quality Assessment", 2009)
"An inherent quality characteristic that is a measure of the degree to which data agrees with an original source of data (such as a form, document, or unaltered electronic data) received from an acknowledged source outside the control of the organization." (David C Hay, "Data Model Patterns: A Metadata Map", 2010) [accuracy in regard to a surrogate source]
"An inherent quality characteristic that is a measure of the degree to which data accurately reflects the real-world object or event being described. Accuracy is the highest degree of inherent information quality possible." (David C Hay, "Data Model Patterns: A Metadata Map", 2010) [accuracy in regard to reality]
"Freedom from mistakes or error, conformity to truth or to a standard, exactness, the degree of conformity of a measure to a standard or true value. (Michael Brackett, 2011)
"The degree to which a data attribute value closely and correctly describes its business entity instance (the 'real life' entities) as of a point in time." (DAMA International, "The DAMA Dictionary of Data Management", 2011)
"Accuracy is the quality or state of being correct or precise; accurate information is correct in all details (NOAD)." (Laura Sebastian-Coleman, "Measuring Data Quality for Ongoing Improvement ", 2012)
"Within the quality management system, accuracy is an assessment of correctness." (For Dummies, "PMP Certification All-in-One For Dummies" 2nd Ed., 2013)
"How closely a measurement or assessment reflects the true value. Not to be confused with precision [...]" (Kenneth A Shaw, "Integrated Management of Processes and Information", 2013)
"Accuracy is defined as a measure of whether the value of a given data element is correct and reflects the real world as viewed by a valid real-world source (SME, customer, hard-copy record, etc.)." (Rajesh Jugulum, "Competing with High Quality Data", 2014)
"Within the quality management system, accuracy is an assessment of correctness." (Project Management Institute, "A Guide to the Project Management Body of Knowledge (PMBOK® Guide)" 6th Ed., 2017)
"The degree to which the data reflect the truth or reality. A spelling mistake is a good example of inaccurate data." (Piethein Strengholt, "Data Management at Scale", 2020)
"The degree to which the semantic assertions of a model are accepted to be true." (Panos Alexopoulos, "Semantic Modeling for Data", 2020)
"The degree of how closely the data represents the true value of the attribute in the real-world context." (Zhamak Dehghani, "Data Mesh: Delivering Data-Driven Value at Scale", 2021)
"Closeness of computations or estimates to the exact or true values that the statistics were intended to measure." (SDMX)
"The capability of the software product to provide the right or agreed results or effects with the needed degree of precision." [ISO/IEC 25000]
"The closeness of agreement between an observed value and an accepted reference value." (American Society for Quality)
"The term “accuracy” refers to the degree to which information accurately reflects an event or object described." (Precisely) [source]